Potato Towers with Tuna and Olives

At Basque bars, when spicy, briny things aren’t skewered, they are usually stacked into decorative towers held together with toothpicks. Bathed in a mild vinaigrette and fancifully arranged on big plates, these variations on the theme of anchovies, tuna, and olives are just what the doctor ordered to stimulate the appetite and soften the effects of alcohol. You can play with this recipe, substituting tomato slices for potatoes as a base or adding poached shrimp to the towers instead of, or