Preheat oven to 350°F Sprinkle fish with salt and pepper; place in 11x7x2" glass baking dish. Drizzle with 1 1/2 teaspoons lime juice.
Heat oil in large skillet over medium heat. Add leek over medium heat. Add leek and garlic; saute 7 minutes. Add coconut milk and remaining lime juic; boil until thick, about 4 minutes. Stir in lime peel.
Spoon sauce over fish. Bake about 20 minutes, until fish is just opaque in center. Transfer to platter. Whisk juices in baking dish. Spoon around fish, top with cilantro.