Special equipment: A food processor or blender
In a food processor puree the fresh coconut, green mango, shallot, yogurt, green chiles, and ginger with as little of the water as needed for a moderately thick consistency. Add the kosher salt and lime juice and puree until blended.
In a skillet, heat the vegetable oil over medium heat. Add the mustard seeds, dried red chiles, and fresh curry leaves, cover and cook until the seeds begin to pop. Stir in the coconut mixture and cook for 15 seconds.
Transfer to a serving bowl. Keeps for 1 or 2 days in the refrigerator.
*Can be found at Asian Markets ** Can be found at Indian and Sri Lankan stores