Chop the cucumber in a food processor or shred. About 1/4-1/2 cup. Wrap in a towel and squeeze to remove as much water as possible. Mix together the yogurt, shredded cucumber, garlic, white wine vinegar, salt and pepper to taste, and lemon juice. Drizzle lightly with olive oil. Refrigerate for at least 30 minutes before serving so the flavors can meld.