Heat oven to 350°. Mix zucchini, tomato, oregano and garlic pepper in medium bowl.
Place 4 tortillas on ungreased large cookie sheet. Sprinkle 1/2 cup of the cheese evenly over each of the 4 tortillas. Spoon one-fourth of the vegetable mixture over cheese. Top with remaining tortillas.
Bake about 6 minutes or until hot and cheese is melted. Cut each quesadilla into 6 to 8 wedges. Serve with spaghetti sauce.