In a skillet, saute garlic in oil until fragrant. Stir in the salmon, basil, and pepper; heat through.
Meanwhile spread butter over one side of the tortillas. Place on a griddle, butter side down. Sprinkle half of each tortilla with cheese and salmon. Top with more cheese, then fold other half over filling.
Cook over medium heat for 1-2 minutes on each side, until golden brown and cheese is melted.
Cut into wedges and serve with guacamole or salsa.