If using fresh corn, remove the kernels from the cobs. If using frozen corn, make sure it's thawed.
In a large skillet, heat the vegetable oil over medium-high heat. Add the corn kernels and cook, stirring occasionally, until they are charred and cooked through, about 8-10 minutes.
Add the chopped white onion, minced garlic, and jalapeño to the skillet. Cook for an additional 2-3 minutes, or until the onions are soft and translucent.
Remove the skillet from the heat and allow the corn mixture to cool slightly.
In a large mixing bowl, combine the cooked corn mixture, chopped cilantro, crumbled Cotija cheese, mayonnaise, sour cream, lime juice, smoked paprika, ground cumin, and chili powder. Mix well to combine.
Taste and season with salt and pepper as needed. You can also adjust the heat by adding more jalapeño or chili powder if desired.
Cover the bowl and refrigerate the Esquites for at least 30 minutes to allow the flavors to meld. This dish is best served chilled or at room temperature.
Before serving, give the salad a good stir, and garnish with additional chopped cilantro, Cotija cheese, and a sprinkle of chili powder, if desired.