What you need:

 *  500 g yoghurt
 *  1 cup water
 *  1 or 2 diced cucumbers (diced is far better than grated, although at many restaurants they grate them)
 *  a couple of spoonfuls chopped dill
 *  salt, vinegar and oil to taste
 *  optional: a couple of spoonfuls chopped walnuts (not in the traditional recipe though)

How to make it:

Mix all the ingredients (starting with the yoghurt and the water) and serve cold in a soup dish. Use enough water so
the soup is about the consistency of milk. Add a couple ice cubes if it's not cold.

If you use all of the above ingredients without the water and strain the yoghurt until it becomes half in volume, you
can make a salad. It is cold suh tarator (dry tarator), or Snezhanka (Snow White) or mlechna salata (yogurt salad).
.