01 - In a large bowl, combine the sliced cucumbers, red onion, and fresh dill.
02 - In a small bowl, whisk together apple cider vinegar, olive oil, sugar (if using), salt, and black pepper until well combined.
03 - Pour the dressing over the cucumber mixture and toss gently to combine.
04 - Let sit for at least 10 minutes before serving to allow the flavors to meld. Serve chilled or at room temperature.