Cook the pasta in boiling salted water to al dente according to the package directions. Drain and rinse under cold water. Let cool completely.
Char the corn over the flame of a gas stove or in a cast-iron skillet or grill pan. Cut the kernels off the cobs and set aside.
Whisk together the sour cream, mayonnaise, lime zest, lime juice, chili powder, smoked paprika, and garlic in a medium bowl.
Combine the cooked pasta, corn, green onions, cilantro, and jalapeño in a large bowl. Add the dressing and half of the Cotija. Toss to coat and season with salt and pepper to taste.
To serve, garnish the top with the remaining Cotija, the cilantro, and lime wedges.