Check the next step before you begin if you are boiling your corn on the cob or are using frozen corn kernels. Cook pasta 1 minute shy of package instructions in a large pot of generously salted water. Drain the pasta and toss with oil. Set aside to cool.
To boil corn on the cob: Add to the pasta water when there's 4 minutes left of cook time. Remove the corn, then drain the pasta and toss with oil, and set aside to cool. If using frozen corn kernels: Add to the pasta water when there's 1 minute left of cook time. Drain the corn and pasta and toss with oil, and set aside to cool. To grill corn on the cob: Preheat the grill to medium high heat, then spray or coat the corn with cooking oil. Grill covered for 10 minutes, turning every 2 minutes until charred on all sides. Remove from the grill and use a sharp knife to slice the kernels from the cob.
Transfer the pasta and corn to a large mixing bowl, and add green onions, cilantro, jalapeño pepper, and cotija cheese.
Whisk together all ingredients for the dressing, except salt.
Drizzle the dressing over the salad and toss to coat. Taste to add salt and adjust seasoning, if needed.
Serve garnished with more chili powder, cilantro, and/or cotija.
