Ninjitsu - UOGuide, the Ultima Online encyclopedia
That doesn't explain fukiya darts and surikens tho but I have played a few ninjas and this is what I have learned about it.
The fukiya darts and surikens can be thrown by a ninja to poison people without actually having the poisoning skill. To poison the darts you will need poisoning, but to USE them you don't need poisoning. Your chance to hit is scaled off ninjitsu skill and they can be parried. Darts can only be used up close, within 2-3-4 tiles. It's been a long time since i've used darts but you need to be close to the target. Surikens you must be at least 2-3 tiles away to use. I'm 99% sure you can't shoot darts or throw stars without a blowgun or a ninja belt. A blacksmith makes the surikens, 1-2 at a time, and the bowfletcher makes fukiya darts, 1-2 at a time also. The tailor makes a ninja belt, or you can go to tokuno islands and kill a ninja they almost always have one. A carpenter makes the blow guns and I am pretty sure you can get them off the ninjas in tokuno also. You can use what ever poison you want to use on them. I was told that if the ninja has poisoning on the template, stars and darts have a chance to do lethal (level 5) poison instead of deadly/parasitic (level4). I have never had this happen, but I havn't played a nox ninja very much, so it mayb true.