Preheat oven to 350 degrees. Dice onions and garlic. Chop yellow pepper, mushrooms and basil.
Assemble the pizzas: Arrange pita breads on two baking sheets. Spread tomato sauce on each. Scatter bell peppers, mushrooms, and basil on top, and then sprinkle with the mozzarella cheese. Transfer the baking sheets to the oven, and bake the pizzas until the peppers begin to wilt and the mozzarella has melted, about 20 minutes. Remove the pizzas from the oven, and transfer to a cutting board. Cut each pita pizza into wedges. Serve warm or at room temperature with kiwi.