4 cucumbers  peeled, leaving stripes of skin, and sliced thin (about 6 cups)
1 cup coarsely shredded carrot
1 cup paper-thin slices red onion (or sweet white onion such as this week’s Ailsa Craig)
1/3 cup white-wine vinegar
3 tablespoons vegetable oil
1 1/2 teaspoons salt, or to taste
1 teaspoon sugar

In a bowl combine vegetables. In a small bowl stir together vinegar, oil, salt, sugar, and pepper to taste until salt and sugar are dissolved. Pour dressing over salad and toss to combine well. Chill salad, covered, stirring occasionally, at least 1 hour and up to 3 hours.

– http://www.epicurious.com