It used to be a tradition among many German farm families in the Midwest to always have a bowl of these vinegary cucumbers in the refrigerator. They're the easiest relish of all, as they require no cooking, and they're a refreshing salad alongside any meal.
Combine water, shallots, vinegar, sugar, dill, salt, and pepper in a large glass bowl, stirring until sugar dissolves. Stir in cucumber. Cover and refrigerate at least 24 hours. Serve with a slotted spoon.
Note: Refrigerate Spicy Cucumber Relish in airtight containers up to one week.