Place fish fillets in a non-aluminum dish.

Combine tequila, triple sec, lime juice, salt, garlic, and 2 tablespoons of vegetable oil.

Pour the mixture over the fish, ensuring it's thoroughly coated.

Cover the dish and marinate for 30 minutes at room temperature or up to 3 hours in the refrigerator, turning occasionally.

Just before serving, combine diced tomatoes, finely minced onion, chopped jalapenos, minced cilantro, sugar, and salt to taste to create the salsa.

Heat the grill to a very warm temperature.

Remove fish from the marinade, pat it dry, reserving the marinade.

Brush the fish lightly with 1 teaspoon of vegetable oil and grind pepper over the surface.

Cook the fish on a greased grill for approximately 4 minutes per side, or until the flesh is opaque.

Meanwhile, boil the reserved marinade in a saucepan for 2 minutes, then remove and discard the garlic cloves.

Spoon a small amount of the boiled marinade over the cooked fish.

Serve the fish with a generous spoonful of the tomato salsa alongside.