I have a hibachi and a gas grill both. On the gas grill, I usually throw a handful or three of woodchips(apple, mesquite and hickory are the only ones available here) that have been soaked in water, and they burn down to a fine ash. It does a decent copy of the flavour you get off of a hibachi, using some local hardwood charcoal. I'm not a fan of the kingsford briquettes.
EDIT: It actually makes textured tofu palatable.....along with the grilled onions, peppers, ketchup, mayo, mustard, relish, cheese, lettuce and tomato...no buns however.
