Salmon skin is easier to remove after cooking, so grill (or broil) the fillets first.
Brush salmon and toss asparagus with olive oil; sprinkle with salt and pepper. Grill salmon over medium-high heat (350° to 400°) for 3 to 5 minutes on each side or until desired degree of doneness. Grill asparagus, turning occasionally, 3 to 5 minutes or until tender.
Divide arugula evenly among 4 plates; top with flaked salmon, asparagus, and tomatoes. Serve with vinaigrette.