Preheat a grill to medium-high heat.
In a small bowl combine the olive oil with the Creole seasoning and set aside.
Cut the fish into fillets about the same size as the bun. Brush both sides of the fish with the seasoned olive oil.
Transfer the fish to the grill and cook for 5 to 6 minutes per side, or until the fish is just cooked through. Transfer the fish from the grill to a platter and set aside.
Spread 1 tablespoon of the Roasted Corn Aioli onto the top half of each bun. Place the fish, lettuce and several slices of the red onion on the bottom of each bun and close the sandwich.
Serve the sandwiches with a lemon wedge and Potato Salad.