Grilled Chicken with Mustard-Tarragon Sauce recipes

Ingredients:4 (6-ounce) skinless, boneless chicken breast halves1/2 teaspoon salt, divided1/4 teaspoon black pepper, dividedcooking spray3 tablespoons minced shallots3 tablespoons Dijon mustard2 tablespoons red wine vinegar2 tablespoons water1 tablespoon extra-virgin olive oil1 teaspoon chopped fresh tarragon1/2 teaspoon sugar4 cups gourmet salad greens