Hiya GDS! So, you are trying to make a list of words which have been incorporated into English, and want interesting (less "obvious") examples, eh? I don't have many examples, but I do have a few thoughts regarding whether the type of words you are looking at actually are English! Allow me to explain...ahem...
You are probably right to exclude items like "tea" - it is now such a part of our way of life. It would probably take a new "Dark Age" with no telly (forget "28 Days Later", I'm talking 28 CENTURIES later!) for us to forget such words in the UK at least (apologies if you hail from elsewhere), so we can simply assume they pose no difficulties for anyone at all. But what about the other words (your focus), though? Are they now accepted as English?
Whilst many such words can be found in the larger English dictionaries, whether they would "roll off the (tip) of the tongue" of the average English SPEAKER is another matter entirely; indeed, a speaker might not go for the loanword at all, choosing instead to paraphrase in English. A main factor is whether or not one has the real-world knowledge of the thing the word represents (we are talking, after all, about exotic imports into our world as well as our language).
For example, one could insist that we all (should) know what "cheongsam" represents, but I suspect many would paraphrase one as a "Chinese dress" (probably due to the difficult pronunciation and/or from not having studied Chinese, or at least loanwords from Chinese into English); and even with my knowledge of Chinese (albeit Mandarin, not Cantonese), I had problems myself committing this word to memory (I can't tell you what the Mandarin is either!)...but then, I am not a transvestite with fantasies about (oriental?) womens' slinky clothing on my mind every waking moment.
I mean, people don't (easily) learn words (in or from whatever language) in a vacuum, and perhaps need a fair bit of "hands on" experience with, in this instance, the silky material, buttons/zips, snappy RUBBER elastic etc of said item of clothing to really get to "know" it, and thereafter stand any chance of USING the WORD that represents the clothing (I was referring to the design of an "SM" choengsam just then, by the way, bet you haven't heard of THEM!!)). And as I said above, there may be difficulties in saying "cheongsam" for the speaker, even if the speaker can appreciate that a cheongsam is indeed what he (or she!) wants to talk about.
Maybe we should look examples of things that we could expect would be easier for e.g. British men to be aware of, "get into"
and finally actually say than "cheongsams". "Sampan" is easier for me, but I can't honestly tell you if it is any different from a "junk" (if "junk" is indeed not only referring to the same thing, but is also a loanword, there is then a battle going on not between native vs. non-native words, but between the loanwords themselves for the hearts and minds of the English! Experts in etymology please also see my above comments on "typhoons" vs. "hurricanes"); in any case, I again suspect a paraphrase along the lines of "Chinese (fishing)boat/trawler" would also "suffice". I need to go to check what these boats look like!!
Perhaps the most interesting word of all to me was "kowtow". I accept that it is used in writing (journalism), but because it has a political ring to it in many examples, and because the average English speaker does not have such extreme demands/orders placed on them (and wouldn't "nod the head" in an oriental way anyway even if they were in such a situation), I don't know if it can really be said to be part of "our" SPOKEN English at all, although it is easy enough to pronounce.
We might need to consider if "kowtow" is, therefore, yet entirely "unrelated to the country it came from" (to paraphrase Wjserson) or "does not refer to concepts specific to the culture from which they come" (to paraphrase GDS). In contrast, those words that seem to have been agreed by Wjserson and GDS to be excluded from consideration (such as martial arts terms) would seem to relate i.e. be relevant to the lives of at least their many practitioners in the west also, and more part of those practioners' everyday parlance and thus their "English" than "kowtow" or similar words are (what MIGHT remain exotic and therefore somewhat "foreign", is the practice of the art or the art itself, not the word for the art!).
So, if you are trying to decide whether words other than "tea" and "typhoon" are part of English, I don't think you can ultimately appeal to anything other than individual use, especially by not just "educated" but more importantly "in-the-know" USERS. When such groups are small, obviously the extent to which the word will penetrate into English generally is limited - it often takes a "boom" or "fad" for the words (but perhaps not the thing it is meant to represent) to become popular enough to be used (or misued) to any noticeable extent (for example, somebody might see Tai Chi and call it "kung fu", due to having only seen the TV series or violent Hong Kong movies).
You could, if you asked the wrong type of people, maybe find out how many words are used in English too generally or INCORRECTLY even! All you would then be describing, however, is ignorance of a foreign culture rather than proper use and genuine knowledge of the foreign words. But perhaps we linguists (unless we are also possibly offended Tai Chi practitioners) just have to accept that meaning is vague, negotiated, temporary, and that we can never capture "the real world" in our descriptions?
I'd therefore like to posit that there are at least four kinds of loanword in English, ranging from "most assimilated" to "still most foreign": those that we may not even be aware were originally foreign, and that everybody uses with no problem; those that are used as possibly inaccurate "blanket" terms; those that are used by some people but paraphrased into English equivalents by others, for whatever reasons; and those that are used accurately, but by only those few who take an interest in the foreign culture and perhaps language. Beyond the last type mentioned, we may as well begin learning or speaking the foreign language itself ("go native")!
I'm referring to what greatdismalswamp was asking for in the beginning, thats all.
Maybe I can now start thinking of words that would be appropriate to GDS's purposes...but my "expertise" in Chinese is maybe not high enough! 