Grease the grill grate by brushing with oil. Preheat the grill to medium-high. Generously sprinkle 4 skin-on salmon fillets (6 to 8 ounces each) all over with salt and pepper. In a small bowl, whisk together the 1/4 cup maple syrup, 4 tbsp (1/2 stick) butter, melted, 2 tbsp Dijon mustard, 2 tsp apple cider vinegar, 1 tsp Worcestershire sauce, and 1 tsp black pepper to make the glaze. Brush the salmon tops generously with the glaze and place skin-side down on the grill and cook, about 4 minutes. Flip the salmon and cook until they reach the doneness you like, about 5 minutes for medium-rare. Carefully remove the fish from the grill and place skin-down on a pretty serving platter.