Season the salmon fillets with salt and pepper and drizzle with olive oil.
Whisk together the mayonnaise, mustard, olive oil, garlic, lemon juice, tarragon, salt and pepper; set aside.
Lightly oil the grill grate. Cook the salmon on the grill until the fish flakes easily with a fork, 5 to 10 minutes. Place on a serving plate and top with the prepared sauce.
