Place salmon, skin side down, on a rack in a broiler pan.
Broil 5 inches from heat (with electric oven door partially open) 12 minutes or until fish flakes easily with a fork. Cool and flake fish.
Stir together sour cream and next 6 ingredients in a large bowl. Toss with salmon, macaroni, and green onions. Cover and chill 2 hours. Serve on lettuce leaves, and garnish, if desired.
*1 (6-ounce) can skinless, boneless salmon, drained and flaked, may be substituted. Omit broiling.