Oil a skillet or cast iron fry pan and place one tortilla shell on the skillet. Spread a thin layer of tomato paste on the tortilla shell. Sprinkle with shredded or sliced cheese. Add any other pizza toppings that you like. Cook over open fire, checking for doneness. Pizza is done when the tortilla shell is lightly toasted and golden brown. Fold in half and cut into pie shaped chunks. Enjoy.