Cucumbers (especially the long, thin seedless variety usually called English cucumbers) are a perfect vessel for appetizers. Simply slice the unpeeled cucumbers into 1-inch lengths, carefully scoop out the center to create a shell, and then mound your favorite salad or savory mousse inside.
Cucumber tastes great with just about everything. There are as many variations on tuna salad as there are cooks, so feel free to adapt to your tastes. Finely diced cornichons or pickles, grated carrot, cumin or caraway are all delicious additions. For more elegant hors d'oeuvres, try lobster or crab; chicken or shrimp salad also work well. Best of all, you can prepare the cucumbers up to a day ahead and fill them a few hours in advance of serving.
This recipe makes about 30 pieces.
Cut the unpeeled cucumbers into 1-inch lengths. With a tiny spoon, carefully scoop out the center of the cucumber, leaving a 1/8- to 1/4-inch-thick shell. Discard the cucumber pulp or reserve it for another use.
Arrange the cucumber shells on a rimmed baking sheet. The cucumbers can be refrigerated, covered, for up to 1 day before filling.
Place the tuna, mayonnaise, celery, scallions, dill, and lemon zest in a medium-size bowl and stir to combine. Season with pepper to taste.
Using a teaspoon, mound some of the tuna salad in each of the cucumber shells. Garnish each piece with a sprig of dill. The cucumbers can be refrigerated, covered, for several hours before serving.