Preheat grill to 450°F, lid closed for 15 minutes.
Brush the grill grate with oil and grill corn, turning occasionally. After about 10 minutes, corn should be cooked through and slightly charred on the outside.
Remove corn from the grill and cut kernels off the cob by standing corn cobs vertically and slicing them downwards.
In a bowl, mix the grilled corn kernels with the remaining ingredients. To serve, top corn with chopped cilantro and sprinkle with cotija cheese. Enjoy!