Does this photo fit your image of a beach town restaurant? No burgers, hot dogs, French fries or milk shakes here. This is the Bistro Langosta, located in the upscale Langosta residential area of Tamarindo. It is open only for dinner and has live music on some nights. A link to Bistro Langosta's website is here.
My wife is a "foodie." She enjoys fine dining, and one of the major reasons we decided to buy a condo in Langosta and another in Tamarindo is that there are more than 50 restaurants in town and many of them offer gourmet dinners, not "beach food."
Like many of the Tamarindo shopkeepers, many of the chefs and restaurateurs are European. In the U.S., many of the Langosta and Tamarindo restaurants would be of the quality that you would expect them to have white table cloths, but in Costa Rica they are casual, usually open air.
There is a wide variety of international cuisine in Tamarindo because almost all the residents and tourists are from foreign countries. I will post more about Costa food in the future.