1. Drain chicken and place in medium bowl. With a fork break up larger pieces and add mayonnaise, Dijon mustard, red onion, celery, lemon juice, lemon pepper seasoning salt, and ground pepper. Refrigerate until chilled.
2. Wash and pat dry lettuce leaves with a paper towel. Add cherry tomato halves to chicken salad and mix lightly to combine. Lay two lettuce leaves on a plate and spoon on chicken salad, sprinkle lightly crushed croutons on top and serve immediately.