Preheat grill to medium heat. Place 4 (97% fat-free) beef franks on grill rack coated with cooking spray; grill, covered, 10 to 15 minutes, turning frequently until done. Place franks in 4 toasted white-wheat hot dog buns. Spread 1/4 cup Cheez Whiz evenly over franks. Place 1/2 cup grilled yellow, red, and green bell pepper slices and 1/2 cup onion slices evenly over dogs.