Place the pitas on a baking sheet lined with parchment paper. Spread ¼ cup of tomato sauce on each pita, leaving border around the edges. Sprinkle ¼ cheese evenly on each pita. Add assorted vegetables of your liking to each pita. You can also use chopped chicken breast or cooked shrimp. Spray the pizzas lightly with olive oil spray and season with salt and pepper. Bake in the oven until pitas are crispy, cheese is melted and vegetables are cooked, 8-10 minutes. Remove from oven, cut and serve. Pizzas can also be cooked in a toaster oven.