In a small mixing bowl stir together brown sugar, lime juice, lime zest, butter, garlic and cayenne pepper.
Place salmon fillets in a dish. Spoon and spread lime mixture over tops and sides of salmon if using skin-on salmon, if using skinless spread mixture over top and bottom of salmon (use up all of the mixture). Let marinate in refrigerator 30 minutes. Preheat oven to 425 degrees.
Line a 13 by 9-inch baking dish with Reynolds Kitchens Unbleached Parchment Paper. Place salmon on parchment, leaving space between fillets. Season with salt and pepper.
Bake in preheated oven until salmon flakes easily with a fork, about 12 - 15 minutes (cook time will vary based on thickness of fillets).
Sprinkle with cilantro and serve warm with lime wedges for spritzing over salmon. Serve over Coconut Rice if desired.
*1/2 tsp is spicy! If you don't like heat then reduce amount to taste or omit.