A sambal provides the perfect foil for the delicate salty-sweet flavor of mussels in this recipe.
Make the sambal paste: In the bowl of a food processor fitted with a metal blade, combine chili sauce, garlic, ginger, hot pepper flakes, cumin, and turmeric. Process until almost smooth.
In a large pot, heat oil over medium heat. Add sambal paste, and cook, stirring occasionally, until fragrant, about 2 minutes. Add onions, and cook until softened, 3 to 5 minutes more. Stir in coconut milk, sugar, and salt. Add mussels, cover, and cook until mussels open and are cooked through, about 5 minutes. Remove from heat, transfer to serving dish, sprinkle with lime juice, and serve immediately.