In the center of the main island Santa Cruz are many opportunities to have dinner. The most popular street is the Avenida Charles Darwin along the coast. Most of the restaurants on this street offer good western food although a little pricey.
A better and way cheaper option to eat fresh seafood is at Calle de los Quioscos. This street is closed for traffic in the evening and every little restaurant provides a few tables. It works like a food-court, so order were ever you want.