Preheat oven to 375 degrees.
In a large baking dish, place the salmon. Season salmon with olive oil, salt and pepper. Place salmon in the oven and bake for 20 minutes, until fish flakes easily with a fork.
In a medium pot over medium heat, add the vinegar, shallot and garlic. Bring vinegar mixture to a boil and cook for 20 minutes, until it has thickened into a sauce.
Place salmon on a bed of lettuce leaves and drizzle sauce over the top. Serve warm.