Prep the cucumber. Grate the cucumber on the large holes of a box grater. Place it in a clean kitchen towel or layered paper towels and squeeze out as much liquid as possible. The drier, the better.
Combine the base. In a medium bowl, add the Greek yogurt, olive oil, lemon juice, garlic, salt, and a few grinds of pepper.
Stir until smooth and glossy.
Fold in the cucumber and herbs. Add the squeezed cucumber, dill, and mint (if using). Mix gently until evenly distributed.
Taste and adjust. Add more salt, lemon, or dill if needed. The flavor should be bright, cool, and balanced, with a gentle garlic kick.
Chill. Cover and refrigerate for at least 30 minutes and up to 24 hours.
This rest time helps the flavors meld and the garlic mellow.
Serve. Swirl into a shallow bowl, drizzle with a little olive oil, and garnish with a pinch of dill. Serve with warm pita, veggies, grilled meats, or as a spread for wraps.