Prep: 11 minutes; Cook: 10 minutes
1. Prepare grill.
2. Sprinkle fillets with salt and pepper. Coat fillets and onion slices with cooking spray. Place fish and onion on grill rack coated with cooking spray. Cover and grill 5 minutes on each side or until fish flakes easily when tested with a fork and onion is tender.
3. Cut onion into bite-sized chunks; break fish into chunks. Place 2 cups salad greens on each of 4 serving plates; arrange grapefruit sections, onion, and fish evenly over greens on each plate. Drizzle Blood Orange Vinaigrette evenly over salads.