Bring a large pot of salted water to a boil. Add fresh corn kernels and cook for 5 to 7 minutes until tender yet crisp. Drain and cool on a baking sheet.

Wash and dice the medium cucumber into bite-sized pieces. Halve the cherry tomatoes and finely chop the red onion. In a large bowl, combine cooled corn, cucumber, tomatoes, and onion.

In a separate bowl, whisk together mayonnaise, sour cream, lime juice, chili powder, and a pinch of salt and pepper until smooth.

Pour the dressing over the vegetable mixture and gently toss to coat without crushing the tomatoes.

Garnish with crumbled feta cheese and chopped cilantro. Serve immediately or chill for up to an hour.