Pour coconut milk into a large measuring cup and add water to make 3 cups. Set aside. Heat coconut oil in a medium pot over medium heat. Add onions and cook until onions are tender, stirring often. Add rice, gingerroot and curry. Cook and stir for one minute. Add coconut milk mixture and salt to rice in pot. Bring to a gentle boil. Reduce heat to low, cover and simmer until liquid is absorbed and rice is tender, about 12 minutes. (Check suggested cooking time on rice packaging.) Remove rice from heat and let stand, covered, for 10 minutes. Fluff rice and add diced pineapple and cilantro. Serve hot.