1 English cucumber, cut in half lengthwise and sliced
½ small red onion, cut in half and thinly sliced
In a salad bowl, add the sliced cucumber, tomatoes, and red onion.
In a small bowl, whisk together the cider vinegar, olive oil, and sugar.
Season to taste with salt and pepper.
Pour salad dressing over salad and gently toss to combine.
Cover and let sit on counter for about 15 minutes for flavors to develop.
Gently toss again before serving.