Combine the first 6 ingredients in a zip-top plastic bag. Add the salmon to the bag; seal. Marinate in refrigerator for 40 minutes, turning once.
Prepare grill.
Remove fish from bag and reserve marinade. Place fish on grill rack coated with cooking spray, skin side down; grill 5 minutes. Brush fish with reserved marinade and discard remaining marinade. Lightly coat fsih with cooking spray. Turn fish over; grill 3 minutes or until fish flakes eaily when tested with a fork. Garnish with onions, if desired. Yield: 4 servings (serving size: 1 fillet)