Wrap tortillas in foil and heat in low oven or in a steamer while the vegetables are cooking. Heat the oil in a large, heavy skillet. Add the onions, peppers and garlic and saute until they begin to soften. Stir in the squash and cook a few minutes longer. Add salsa, cumin and salt; cover and cook about five minutes. Divide the vegetables between the tortillas, top with cheese and cilantro. Roll up and serve with beans on the side.