Grilled Cajun Chicken Sandwich

Ingredients

• 6 boneless skinless chicken breast halves (4 ounces each)
• 1 tablespoon olive oil
• 1/2 teaspoon celery salt
• 1/2 teaspoon garlic salt
• 1/2 teaspoon lemon-pepper seasoning
• 1/4 teaspoon cayenne pepper
• 1/4 teaspoon paprika
• 1/4 teaspoon pepper
• 6 kaiser rolls, split and toasted
• 12 slices tomato
• 6 lettuce leaves
• sliced red onion, optional