Cut tenderloin crosswise into 12 slices, approximately 3/4-inch thick. Place each slice on its cut surface and flatten with heel of hand to 1/2-inch thickness. Combine crumbs, Parmesan cheese, salt and pepper; dredge pork slices to coat.
Heat oil over medium-high heat in nonstick pan. Saute pork for 2 to 3 minutes per side; remove and keep warm. Add onion, garlic and zucchini or squash to skillet and saute 5 minutes or until tender.