Mix all the sauce ingredients in a bowl, adjusting sweetness and spice as desired.
For steaming, line a bamboo steamer with parchment paper and steam the dumplings for 12-15 minutes.
For boiling, bring a pot of water to a boil and cook the dumplings directly from frozen for 3-4 minutes until they float. Save some of the dumpling water if needed.
Serve the dumplings with the sauce either as a dip or poured over. Garnish with scallions and coriander. Add more chili oil or sauce if desired.