Pour the yogurt in a large mixing bowl. Whisk it to make it smooth.
Cut the cucumber to very tiny cubes. Do not grate or use a processor if possible; if you do the cucumbers become messy and watery.
Add the cucumber to the yogurt. Mix. Add cold drinking water until you have a thick texture. Do not forget this is supposed to be eaten with a spoon, like a soup. Some like it really watery, some with some thickness. Make it according to your taste.
Add salt, dry mint flakes. Mix
You can also add chopped dill, red pepper flakes and a tablespoonful of extra virgin olive oil. But these are optional.
Serve a large ladleful for every person in a small bowl. Serve chilled and enjoy.