Mix oil and vinegar together in a small bowl.

Arrange salmon fillets in a shallow baking dish. Rub garlic onto salmon, then pour oil and vinegar mixture over top, turning once to coat. Season with garlic salt, then scatter cilantro and basil over top. Let sit for 10 minutes.

Meanwhile, set an oven rack about 6 inches from the heat source and preheat the oven's broiler.

Remove salmon from marinade and shake off excess. Reserve a few tablespoons marinade for basting; discard the remaining marinade.

Broil salmon in the preheated oven, turning once and brushing occasionally with reserved marinade during the first 6 to 8 minutes of cooking, until browned on both sides and fish flakes easily with a fork, 10 to 12 minutes.