Preheat a grill to medium. Place the salmon in a resealable plastic bag and pour in 1/4 cup vinaigrette. Let stand for 10 minutes.
Place the salmon skin side down on the grill, cover and cook, turning once, until lightly charred, about 6 minutes.
Mound the lettuce on 4 plates, then top each with a piece of salmon and some cucumber, avocado and carrot. Drizzle each stack with 1 tablespoon vinaigrette and top with sprouts.
