Prepare the Cucumbers: Peel the cucumbers and slice them as thinly as possible for better flavor absorption. If using red onion, slice it thinly as well.

Make the Dressing: In a large bowl, whisk together sour cream, dill, white vinegar, sugar, garlic powder, salt, and black pepper until smooth.

Combine: Add the sliced cucumbers (and red onion, if using) to the bowl with the dressing. Toss gently to ensure all slices are well coated.

Chill: Cover the bowl and refrigerate for at least 1 hour to allow the flavors to meld and the cucumbers to release some of their moisture, enhancing the dressing’s consistency.

Serve: Give the salad a gentle stir before serving. Garnish with additional fresh dill if desired.