Bring a large pot of salted water to a boil. Add pasta and cook until al dente, about 7–9 minutes. Drain and rinse under cold water.

Dice red onion, halve cherry tomatoes, and chop cilantro. Soak onion in cold water if desired.

In a small bowl, whisk together mayonnaise, lime juice, and chili powder. Season with salt and pepper.

In a large bowl, combine cooled pasta, corn, diced vegetables, and crumbled cotija cheese. Fold gently.

Pour dressing over pasta mixture and toss to coat evenly.

Cover and refrigerate for at least 30 minutes before serving. Stir and adjust seasoning if needed.