In a large mixing bowl, combine the corn, diced cucumber, cherry tomatoes, and red onion.
In a separate small bowl, whisk together the mayonnaise, sour cream, lime juice, chili powder, garlic powder, salt, and pepper until smooth.
Pour the dressing over the corn and vegetable mixture, and gently toss to combine until everything is well coated.
If using, fold in the chopped cilantro and crumbled feta cheese for added flavor.
Cover the salad and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve chilled as a refreshing side dish.