In a large pot, heat 2 tablespoons oil over medium. Add onion, ginger and garlic and season with salt and pepper. Cook, stirring occasionally, until softened, about 3 minutes. Add miso and cook, stirring frequently, until miso is lightly caramelized, about 2 minutes.
Add coconut milk and 3 cups water and bring to a boil over high heat. Cook until liquid is slightly reduced, about 5 minutes.
Stir in salmon, reduce the heat to medium-low and simmer gently until just cooked through, about 5 minutes. Turn off heat and stir in spinach and lime juice.
Divide rice among bowls. Top with salmon curry, basil and cilantro. Serve with lime wedges for squeezing on top.
