Bring a large pot of salted water to a boil over high heat. Add corn and cook until tender, about 5 minutes. Drain.
Place a thick wooden skewer or dowel lengthwise up through base of each ear of corn. Working with one ear at a time, spread a tablespoon mayonnaise over kernels. Using a spoon, sprinkle 1/2 cup queso fresco over mayonnaise. Season with cayenne pepper and serve with lime wedges.