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.