Heat canola oil in a 4-quart Dutch oven over medium-high. Add shallots, ginger, and garlic; cook, stirring often, until shallots are tender, about 5 minutes. Stir in curry paste, and cook until fragrant, about 1 minute. Stir in wine, and cook until liquid almost evaporates, 2 to 3 minutes. Add coconut milk, lime juice, fish sauce, and 1/2 teaspoon salt. Cover and cook until the mixture comes just to a simmer, 5 to 7 minutes.
Sprinkle remaining 1/4 teaspoon salt over fish; place fillets in a single layer in simmering liquid in Dutch oven. Cover and cook until fish flakes easily with a fork, 7 to 9 minutes.
Meanwhile, heat sesame oil in a large skillet over medium-high. Add bok choy; cook, stirring often, until browned and tender, about 6 minutes.
Using a spatula, transfer fish to 4 bowls. Ladle broth evenly over fish; add bok choy. Garnish with cilantro, and serve with lime wedges.