The clown in my pic bites me every time my hand goes in the tank, which has been frequently recently as I've gotten a lot of new corals. Interestingly enough, it looks like it turned out to be the male even though it was the only clown for a year. The tiny one I got after it very quickly outgrew it, but they get along quite well. If I need to do a lot of work, I catch Whitey in a tupperware and cover it outside the tank to avoid the constant biting.
As for your fanged beast, I definitely wouldn't encourage the jumping for food. I highly doubt you could modify it's behavior, but definitely don't encourage it. Add the food quickly and broadcast it, or use forceps and get them into the water with food for it to take.
LOL yes - the jumping took me completely by surprise on day 3 when I owned him. he was always really friendly - even when not feeding he would either sit in his little area he's made for him self under a coral - and literally stare directly at me. Or if I was in the room - go to the glass and just look out without moving. (he also does this with the cat lol) - perhaps I should make sure the cat doesn't jump on the tank.
However - even when not feeding - just putting my hand/arm in the tank to move something - is interesting. its not like he is attacking it - its more like just 'testing it'.