Most of us think of shrimp as a main ingredient, not a seasoning. All over China and Southeast Asia, however, dried shrimp are used to add a briny note to a wide variety of foods. Often used whole, they are also ground into a powder for such dishes as the Spicy Lemongrass Salad. Dried shrimp are made by salting fresh ones to extract their moisture; they are then sun-dried, which helps concentrate their flavor. Look for them at Chinese and Southeast Asian markets in plastic containers. They range in size from one to one and a half inches; select ones that are bright orange. We keep them for up to a year in the freezer, where they remain on call to add a burst of flavor to some of our favorite dishes.