Preheat oven to 450° F.
Combine first 6 ingredients in a bowl; stir until blended. Cover mixture, and chill.
Place fillets in an 11 x 7-inch baking dish coated with cooking spray.
Place bread in a food processor; pulse 10 times or until coarse crumbs measure 1/2 cup. Combine crumbs and butter in a bowl; stir well. Spoon over fillets.
Bake at 450° for 15 minutes or until crumbs are browned; cover loosely with foil, and bake an additional 12 to 15 minutes or until fish flakes easily when tested with a fork. Serve with chilled cucumber salsa.