Place fish in a shallow baking dish
In a bowl, stir together the tequila, orange liqueur, lime juice, 1 teaspoon salt, garlic, and olive oil
Pour mixture over fillets, and rub into fish
Cover, and refrigerate for 1/2 hour, turning the fillets once
Preheat the grill for high heat
In a medium bowl, toss together the tomatoes, onion, jalapeno, cilantro, and sugar
Season to taste with salt
Set salsa aside
Remove fillets from marinade, and pat dry
Brush the fillets with oil, and sprinkle with ground black pepper
In a small saucepan, boil remaining marinade for several minutes
Remove from heat, and strain out garlic cloves
Set aside to cool
Grill fish for 4 minutes per side, or until fish is easily flaked with a fork
Transfer fillets to a serving dish
Transfer the fish to a serving plate
Spoon salsa over the fish, and drizzle with the cooked marinade to serve