Note: If you prefer some chunks of mango in your sauce, add some extra diced mango pieces to the sauce during the last 5 minutes of cooking.Heat the coconut oil in a Dutch oven over high-sided skillet over medium-high heat. Add the onion and saute until soft and translucent, 4-5 minutes. Add the garlic, ginger, chili pepper, red curry paste and curry powder and cook for another minute. Add the mango and cook for another 2-3 minutes. Stir in the coconut milk and fish sauce and simmer for 10 minutes. Transfer to a blender (careful, it's hot) or use a blend stick and puree until smooth. Return the sauce to the skillet, add the chicken and kaffir lime leaves and simmer for 10-15 minutes, or until the chicken is cooked through, stirring occasionally. Add more salt as needed. If you prefer it sweeter you can add a pinch of sugar. If you like it more savory, add some more fish sauce. Add some fresh lime juice to taste. Discard the lime leaves.Serve with steamed jasmine rice and/or roti garnished with cilantro and some lime wedges if desired. For a pop of red you can also add some sliced red Thai chilies. Crushed dry-roasted salted cashews also make a nice topping for some contrasting crunch.