Mix together the olive oil and balsamic vinegar in a small bowl. Arrange the salmon fillets in a shallow baking dish. Rub garlic onto the fillets, then pour the vinegar and oil over them, turning once to coat. Season with cilantro, basil, and garlic salt. Set aside to marinate for 10 minutes.
Preheat your oven's broiler.
Place the salmon about 6 inches from the heat source, and broil for 15 minutes, turning once, or until browned on both sides and easily flaked with a fork. Brush occasionally with the sauce from the pan.