Preheat oven to 450°.
To prepare grouper, combine cornmeal, salt, and red pepper in a shallow dish, stirring well with a fork. Place milk in a shallow bowl.
Dip each fillet in milk; dredge in cornmeal mixture. Place fish on a baking sheet coated with cooking spray. Bake at 450° for 10 minutes or until fish is done, turning once.
To prepare tartar sauce, combine mayonnaise and next 5 ingredients (mayonnaise through Worcestershire), stirring with a whisk.
Spread about 2 tablespoons tartar sauce over cut sides of each bun; place one fish fillet on bottom half of each bun. Top fillets with the remaining bun halves.