Using a mandoline or sharp knife, slice the cucumbers into thin (1/8 inch) slices.
Transfer to a large mixing bowl.

Slice the onion into thin slices and finely chop the fresh dill. Add both to the mixing bowl with the cucumbers.

In a small bowl, combine the white wine vinegar, sugar, salt and pepper. Whisk well using a fork or small whisk.

Pour the dressing over the cucumbers, onions and fresh dill. Stir to coat.

Serve immediately or refrigerate until ready to serve.

Store leftovers in an airtight container in the refrigerator for up to 4 days.