In a mixing bowl, toss the turkey, celery, onion, tarragon, and mayonnaise. Season with pepper to taste. Stir to combine. Add more tarragon to taste if needed.
Lightly toast the bread, top with the Turkey Salad, tomatoes, and cheese. Place on a baking sheet under the broiler and cook until the cheese has melted.
Serve with chips and pickle. Garnish with parsley.