In a large bowl, combine the sliced cucumbers, halved cherry tomatoes, and thinly sliced red onion.
In a separate bowl, mix together the sour cream, mayonnaise, apple cider vinegar, garlic powder, dried dill, salt, and pepper until smooth.
Pour the dressing over the cucumber and tomato mixture, and gently toss to coat all the vegetables evenly.
Cover the salad and refrigerate for at least 30 minutes to allow the flavors to meld.
Before serving, give the salad a gentle stir and adjust seasoning if necessary.