Bring a large pot of salted water to a rolling boil and add fresh corn kernels. Cook for about 5-7 minutes until tender yet crisp. Drain and spread on a baking sheet to cool.

While the corn cools, wash and dice the cucumber, halve the cherry tomatoes, and finely chop the red onion. Combine cooled corn with cucumber, tomatoes, and red onion in a mixing bowl.

In a separate bowl, whisk together the mayonnaise, sour cream, and lime juice until smooth. Add chili powder, salt, and pepper to taste, mixing well.

Pour the dressing over the vegetable mixture and gently toss to combine and coat all ingredients evenly.

Crumble feta cheese over the salad and sprinkle with fresh cilantro. Serve immediately or refrigerate for up to an hour to let flavors meld.