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. Spread 1 tablespoon reduced-fat cream cheese on bottom half of each of 4 toasted white-wheat hot dog buns. Place franks in buns. Sprinkle 1/2 cup sauerkraut, 1/4 cup pickle relish, and 1/4 cup chopped onions evenly over franks.