Place the oil in a wide-bottomed pot set over medium-high. Add the ginger, onion, garlic and chilies cook 30 to 60 seconds. Add the beer and soy sauce, bring to a simmer, and cook 1 minute. Add the mussels, cover, and cook just until they open. Transfer the mussels to serving dishes, top with its cooking liquid, sprinkle with cilantro or green onion, and enjoy
Note: Discard any mussels that do not close when tapped before cooking, or do not open after cooking. Both are signs the mussel was dead prior to cooking and should not be eaten.