Line a plastic sieve or colandar with a large coffee filter or cheesecloth
. Place over a deep bowl. Put yogurt into the colandar, cover with wax paper and refrigerate for 24 hours or until liquid no longer drains from yogurt. Remove yogurt and place in a bowl. Discard liquid. Stir vinegar, oil garlic and chopped cucumber into yogurt. Season with salt and pepper to taste. Cover and refrigerate 1 hour before serving. Makes 12 servings.