Peel cucumbers only if skin is very tough. Cut cucumbers in half lengthwise and remove seeds with a spoon. Finely dice cucumbers (1/4-inch cubes), or purée in a food processor. Transfer cucumbers to a large bowl. Add vinegar, olive oil, salt, pepper, garlic, chives, mint and dill and stir well. Stir in yogurt and sour cream. Taste and adjust seasoning. Refrigerate at least 1 hour (and chill bowls, as well).
Check soup texture. If it's thick, add a little water; if it's thin, add a little sour cream. Taste and adjust seasoning again, ladle into bowls, garnish with dill and serve.
Nutrition information per each of 8 servings:
Calories232Fat13 gSodium810 mgSaturated fat5 g
Carbohydrates20 gCalcium325 mg