Mix cucumber and salt. Add mixture to a strainer. Place the strainer on a bowl to collect the liquid. Cover and leave overnight in the refrigerator. Skip this step if you are in a hurry and want to make tzatziki right away.
Mix yogurt, vinegar and garlic and store in a container overnight so the flavors can develop. Skip this step if you are in a hurry and want to make tzatziki right away.
Take the cucumber out of the refrigerator and squeeze the remaining liquid out of the cucumber (or place the cucumber with salt in a towel. Squeeze the towel to extrac the liquid from the cucumber for a fast way to extract the liquid). Transfer cucumber to a mixing bowl.
Take yogurt mixture out of the refrigerator and add to the cucumber mixture (or add yogurt, vinegar and garlic straight to a mixing bowl to combine with the cucumber). Add olive oil, freshly ground black pepper and dille. Stir to combine.
Transfer to a serving bowl. Drizzle a bit of extra olive oil on top and a sprig of dille for decoration.