Wrap tortillas in aluminum foil and place in the oven. Turn the heat to 350 degrees F (175 degrees C). Bake for 15 minutes or until thoroughly heated.
Meanwhile, in a 10-inch skillet, heat oil over medium-high heat. Add onions, red and green peppers, and garlic; stir to coat with oil. Cover, reduce heat to medium, and cook for 5 minutes. Stir squash into vegetables. Stir in salsa, cumin, and salt. Cover, and cook for 5 minutes.
Spoon vegetable mixture evenly down the centers of warm tortillas, and sprinkle with cheese and cilantro. Roll up tortillas, and serve.
