In a large saucepan, heat the oil over medium-high heat. Add the rice and stir to coat with the oil. Add the coconut milk, water, and salt; bring to a boil. Stir in the mango. Cover, reduce heat to low, and simmer about 20 minutes or until the liquid is absorbed.
Remove the rice from the heat and fluff with a fork. Place a clean, dry dish towel over the pan, cover with the lid, and let steam for 5 minutes before serving.