Get a chop stick and cut the top so that it can separate slightly. Stick a cricket's leg in the separated part, not too tight, but just tight enough. Hold the stick out to your cham and see if he'll eat it. If he doesn't starve him for the first half of the day and try again later that day. He should eat from it when he's hungry. Every couple of days move your hand up the chopstick a little so he gets used to your hand by his food. Eventually you can eliminate the chopstick all together. Thats what I did!
EDIT: Be very, very, very still. Your arm may get tired, but don't give up!