1. Heat oil in medium saucepan over medium heat until shimmering but not smoking; off heat, add garlic, ginger, curry paste, and sugar and cook, stirring constantly, until fragrant, about 30 seconds. Add coconut milk, lime juice, fish sauce, and water; increase heat to high and bring to boil; boil until sauce is reduced to about 1 cup, about 3 minutes. Off heat, stir in cilantro and season to taste with salt and pepper. Cover to keep warm and set aside; stir once after about 1 minute.

2. To serve, stir sauce to recombine and spoon 1/2 cup over fish. Serve immediately with lime wedges, passing remaining sauce separately.

Makes about 1 cup