01 - Bring a large pot of salted water to a boil. Cook fusilli or rotini according to package directions until al dente. Drain and rinse under cold running water to halt cooking. Set aside to cool completely.
02 - Place corn ears on a hot grill or grill pan over high heat. Turn occasionally until kernels are lightly charred and smoky, about 8 to 10 minutes. Let cool, then stand each ear upright and slice kernels off the cob. If using frozen corn, sauté in a dry skillet over high heat until lightly charred.
03 - In a large salad bowl, whisk together mayonnaise, sour cream, lime zest, lime juice, chili powder, smoked paprika, cayenne pepper, sea salt, and black pepper until smooth and well combined.
04 - Add the cooled pasta, grilled corn kernels, diced red bell pepper, finely diced red onion, sliced green onions, and chopped cilantro to the dressing. Toss thoroughly until every component is evenly coated.
05 - Gently fold in the crumbled cotija cheese. Add diced jalapeño and avocado if desired, folding carefully to keep avocado pieces intact.
06 - Cover and refrigerate for at least 30 minutes so the flavors meld together. Taste before serving and adjust salt, pepper, or lime juice as needed.