Remove mussels from their bag and soak in a large bowl of cold water with 2-3 tablespoons of fine sea salt for 30 minutes. After soaking, rinse under cold water and remove the wirey beards with a small knife.
In a large pot, add the vegetable oil over medium heat. When the oil is hot, add the sliced onion and green chili. Let sweat for 3 minutes. Avoid browning the onion. Add the mussels, Coconut Curry sauce and beer. Cover and let steam over medium heat, about 7 minutes. The mussels will open and become firm when they are fully cooked. They should remain plump and tender.
Serve warm with the cooking sauce and lime wedges or over Basmati or white rice.
