I use soft-taco-sized flour tortillas and a heated nonstick frying pan: wet the tortilla on both sides quickly under running water, place in pan, flip over after about 3 seconds, place grated cheese, a little salsa, a little shredded, cooked chicken, a little whatever on one half of the tortilla, fold over and tamp down the edges with the end of a wooden spoon or something (I use the handle of one of my faithful Chicago knives), leave for a minute or two and flip to brown on the other side. The trick is to heat, flip, and fill the tortilla quickly, before the wet edges dry out--that way they'll stick together when you tamp them down (you can always sprinkle more water along the edges if the timing gets away from you).