Heat your grill on high for 5 minutes then turn down the heat to medium.
Spray the corn with avocado oil and grill on high for about 5 minutes, turning every couple minutes.
Transfer to a cutting board and cut off the kernels.
In a large bowl, combine the corn kernels, avocados (make sure they are the most perfectly ripe avocados), onion, tomato, lime juice, cilantro crumbled cotija, salt, and pepper.
Use two butter knives to criss-cross cut the avocado, turning the bowl to cut it into chunks.
This will keep the acovados chunky but still combine everything together.
Transfer to a serving bowl and top with any extra corn kernels, some crumbled cotija and some cilantro.