In a large resealable plastic bag, combine the first six ingredients; add salmon. Seal bag and turn to coat. Refrigerate for 1 hour, turning once.
Drain and discard marinade. Using long-handled tongs, moisten a paper towel with cooking oil and lightly coat the grill rack. Place salmon skin side down on grill rack. Grill, covered, over medium-hot heat or broil 4 in. from the heat for 15-20 minutes or until fish flakes easily with a fork. Sprinkle with sesame seeds and onions.