Preheat oven to 350°F. Mix tomatoes, avocado, 2 tablespoons lime juice, onion, cilantro, and 2 teaspoons jalapenos in small bowl. Season with salt and pepper. Place fish in single layer on small rimmed baking sheet. Mix garlic, 3 tablespoons lime juice, and 1 teaspoon jalapenos in another small bowl. Drizzle half of lime juice mixture over fish; reserve remainder. Sprinkle fish with salt and pepper; let stand 15 minutes. Meanwhile, wrap tortillas in foil, enclosing completely. Place in oven until heated through, about 15 minutes. Preheat broiler. Broil fish just until opaque in center, about 6 minutes. Cut fish into 1-inch pieces. Top each tortilla with 1/2 cup lettuce, then fish pieces. Drizzle with reserved lime juice mixture. Spoon salsa over; sprinkle with cheese.