In a large mixing bowl, combine sliced cucumbers, halved cherry tomatoes, and finely sliced red onion.

In a separate small bowl, whisk together apple cider vinegar, olive oil, granulated sugar or honey, salt, black pepper, and dried oregano until well combined.

Drizzle the prepared dressing over the vegetable mixture and gently toss the salad.

Cover the bowl with plastic wrap or transfer to an airtight container and refrigerate for at least 30 minutes.

Just before serving, sprinkle chopped fresh parsley or dill over the marinated salad.