1. In a small saucepan, heat the oil until almost smoking. Add the onions and quickly brown until some of the small pieces are crispy and dark brown.
2. In a large bowl, place the shredded carrots. Add the onions and oil from the saucepan and then carefully toss with your hands.
3. Add sugar and toss with your hands again to evenly distribute.
4. Add the salt and pinch or more of red pepper flakes and again toss with your hands.
5. Finally, add the vinegar, cilantro and pepper and give one final toss. Taste and add salt if desired.