Instructions:
1. Prepare the cucumbers: Peel the cucumbers (optional) and thinly slice them. You can use a mandoline for even slices if you prefer.

2. Mix the ingredients: In a large bowl, combine the cucumbers, red onion, and fresh dill.
3. Make the dressing: In a small bowl, whisk together the vinegar, olive oil, sugar (if using), salt, and pepper until well combined.

4. Toss the salad: Pour the dressing over the cucumber mixture and toss everything until evenly coated.
5. Chill and serve: Let the salad sit in the fridge for at least 20-30 minutes before serving, allowing the flavors to meld.

Enjoy this cool, tangy salad as a side dish for grilled meats, sandwiches, or just as a light snack!