Preheat grill to medium heat. Thinly slice 1 radish. Pit, peel, and chop 1 avocado. Chop fresh cilantro, if desired. 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 into each of 4 toasted white-wheat hot dog buns; spoon 1 cup pico de gallo evenly over top of dogs. Sprinkle evenly with radishes, avocado, and cilantro, if desired.