Brush corn with oil. Grill corn over medium-high heat turning occasionally for about 10 minutes or until charred marks start to occur. Remove from heat and set aside. Slice kernels off the cob and place in bowl. You should have approximately 4 cups of corn kernels.
Add jalapeno, red onion and cilantro to corn.
In a small bowl, whisk together mayonnaise, lime juice, garlic and cayenne powder.
Pour dressing over corn mixture, mix. Top with cotija cheese.
Notes
You should have ~4 cups of corn kernels. If cotija cheese is not available, feta may be substituted.