Peel the cucumber and roughly grate it in a slightly larger bowl. Add vinegar, oil, salt, dill and pepper and stir vigorously. Then cover and let stand for about half an hour. Add the cold milk and stir again.
Now you can add vinegar or salt, depending on your taste.
The salad is more of a cold cucumber soup but without cooking. It tastes best in summer, a hearty cool down on hot barbecue evenings.