In a medium mixing bowl, stir together the cherry tomatoes, red onion, mushrooms, artichoke hearts, pepperoni, pizza sauce, mozzarella cheese, vinegar and garlic powder. Warm in the microwave for 1 minute.
Cut each pita in half and warm in the microwave, about 30 seconds. Stuff each with a lettuce leaf; fill each pita with the pizza salad and serve.