
Prepare the cucumber. Grate the cucumber and place it in a paper towel. Press firmly to remove as much moisture as possible.
Make the tzatziki sauce. In a mixing bowl, combine the Greek yogurt, fresh lemon juice, salt, grated garlic, onion powder, white pepper, and black pepper. Add the dried cucumber and stir everything together until well combined.
Chill and serve. Refrigerate until ready to serve, ideally for at least 30 minutes to let flavors meld.