Preheat the oven to 400℉. Place four small flour tortillas on a baking sheet. Brush with vegetable oil.
vegetable oil, 4 flour tortillas
Spoon the pizza or pasta sauce on each tortilla and spread within a ¼ inch of the edge. Top with onion, pepperoni, and cheese.
4 tablespoons pizza or pasta sauce, ½ cup thinly sliced onion, 20 slices pepperoni, 1 cup shredded mozzarella cheese
Bake the tortilla pizzas at 400℉ for 5 to 10 minutes until the cheese is melted and everything is heated through.
Remove from the oven and remove pizzas from the baking sheet to a cutting board. Slice with a knife or pizza cutter into 4 or 8 wedges. Serve.