Prepare the Cucumbers: Slice the cucumbers thinly using a sharp knife or a mandoline for even slices. Place them in a mixing bowl.

Add Red Onion: Thinly slice the red onion and add it to the bowl with the cucumbers.

Prepare the Dressing: In a separate small bowl, whisk together the white vinegar, olive oil, sugar, salt, and black pepper until the sugar is dissolved.

Combine: Pour the dressing over the cucumbers and onions. Add the chopped dill and, if desired, the minced garlic. Toss everything together until well-coated.

Chill: Let the salad sit in the refrigerator for at least 10 minutes before serving to allow the flavors to meld.

Serve: Stir the salad once more before serving. Enjoy as a refreshing side dish or appetizer.