This was an accidental discovery, but so glad it happened. I re-heated a hamburger patty in the microwave the other day after grating some Cotija cheese on it. When I removed it I had these nice little pieces of crispy cheese....wala!!!
Use a very fine grater or microplan and grate cheese. Make mounds of grated cheese on plate (small or large).
For microwave, small mounds brown and crisp up in about 1 min. and 20 seconds. You can cook them in a non stick skillet on med high, time will vary, approx 3-4 min. The more brown you get on each, the crispier it is.