Thinly slice the cucumbers into rounds, about 1/8-inch thick.
Peel and thinly slice the red onion into half-moons.
In a large bowl, combine the sliced cucumbers and onions.
Sprinkle with 1 teaspoon kosher salt and toss to coat evenly.
Let the vegetables sit for 10 minutes to draw out excess moisture.
While vegetables rest, make the dressing: whisk together white wine vinegar, olive oil, and sugar in a small bowl until sugar dissolves.
Drain any liquid that has accumulated from the cucumber-onion mixture.
Add the chopped fresh dill to the vegetables.
Pour the dressing over the cucumber and onion mixture.
Toss everything together until well coated.
Let the salad marinate for at least 15 minutes before serving.
Season with freshly ground black pepper to taste just before serving.
