Preheat oven to 375°.
Combine mayonnaise and 1/2 teaspoon Creole seasoning in a small bowl; cover and chill.
Split rolls lengthwise, cutting to, but not through, other side. Place on a baking sheet; coat insides of rolls with cooking spray. Bake at 375° for 4 minutes or until lightly toasted. Set aside.
Sprinkle 1 teaspoon Creole seasoning over shrimp; set aside.
Heat oil in a large nonstick skillet over medium-high heat. Add onion; sauté 4 minutes. Add shrimp; sauté 4 minutes or until shrimp are done.
Spread mayonnaise mixture evenly over cut sides of rolls; top each evenly with lettuce and tomato. Spoon shrimp mixture over tomato. Serve immediately.