Tarragon Chicken Salad Sandwiches

2 cups chopped or shredded roasted or grilled chicken
1/4 cup finely chopped celery
3 tablespoons mayonnaise
1 tablespoon Dijon mustard
1 tablespoon finely chopped fresh tarragon, or more to taste
Salt and freshly ground black pepper, to taste
Lettuce leaves
Thinly sliced red onion
Wheat or white bread
Pickles for garnish
Place chicken and celery in medium bowl.
In small bowl, mix mayonnaise, mustard, tarragon and salt and pepper to taste; add to chicken mixture and toss until combined.
Toast wheat or white bread, as desired Place a lettuce leaf or two on a slice of bread; mound with chicken mixture, and top with sliced red onion and second slice of bread.
Makes 4 to 6 sandwiches.