1. In skillet, heat oil, add onions to saute until tender, when half way done, add the peppers and squash, cook to desired tenderness. Add tomatoes at the very end so they are not over cooked, just heated through.
2. Heat griddle or a clean skillet over medium heat. Lightly spray top of tortilla shell, place the vegetables and meat on 1/2 of the inside of the tortilla, top with cheddar cheese.
3. Fold quesadilla over and cook on each side till golden brown. Note: The whole wheat tortilla will brown just slightly.
4. Continue this process until all vegetables and meat have been used. Serve with salsa and sour cream. Enjoy!