Zest the outside of 1 lemon into a medium-sized bowl. Add thyme and garlic to bowl and mix with lemon zest. Set aside
Brush 1 teaspoon of oil over salmon. Add salt and pepper to taste. Spread garlic mixture over fish.
Slice one of the lemons into 1/4 inch thick slices. Place salmon (skin side down) and lemon slices on the grill, medium heat. Wait 5 minutes, and place grilled lemon slices on top of fish. You do not have to flip fish.
Cook fish for another 10-15 minutes or until it reaches an internal temperature of 145F. Remove from grill and squeeze half of the second lemon on top.
Plate fish, garnish with a sprig of thyme and enjoy!