Place the yogurt in a paper towel-lined sieve over a bowl. Grate the cucumber place it in another paper-towel lined sieve over another bowl. Let drain for at least an hour both bowls. I did it for 2 hours but have done over-night in the fridge. When you get ready to make the sauce, take the paper towel with the cucumber and wring it out until there is no water coming out.
Add the cucumber to the yogurt. Mix in the sour cream, vinegar, lemon juice, garlic, dill and 1 teaspoon salt. Serve it immediately. The longer it sits the better the flavors are.