Catfish Sandwiches With Creole Mayonnaise

Name: Catfish Sandwiches With Creole Mayonnaise
Ingredients: cooking spray; 4 (6 ounce) catfish fillets; 1 1⁄2 teaspoons cajun seasoning; 4 hamburger buns; 3 tablespoons fat-free mayonnaise; 1 1⁄2 teaspoons shallots, minced; 1 1⁄4 teaspoons whole grain Dijon mustard; 1⁄2 teaspoon fresh lemon juice; 4 lettuce leaves (curly leaf); 4 slices tomatoes; 8 teaspoons sweet pickle relish