I usually clean the crabs before cleaning-I don't like the idea of the meat I'm eating stewing with all the crap and guts inside the body-it tends to make the meat a bit more bitter. To kill/clean the crabs, I usually just grab one section of legs from behind so the crab is facing away from me, I place it on the edge of the sink, and just lift off the top shell-you have to tug a bit, but it comes off pretty easily. With the top shell off, they can't see anything, so you probably won't get bit, but you might want to wait a few minutes if you don't flailing limbs. If you're lazy, steam the crabs, then serve with a dipping sauce that's equal parts minced ginger, soy sauce, and rice wine.