Tarragon-Caper Egg Salad Sandwiches with Smoked Salmon

Ingredients

• 6 hard-boiled large eggs, peeled
• 1 tablespoon finely chopped shallot
• 2 teaspoons finely chopped fresh tarragon leaves
• 2 tablespoons drained capers, rinsed and finely chopped

• 1/2 cup mayonnaise
• 6 (4 to 5-inch) soft round seeded rolls, split
• 18 watercress sprigs, tough stems discarded
• 1/4 pound sliced smoked salmon