Place oil in a large frying pan, wok, or karhai over medium heat. When hot, add urad dal. As soon as it begins to change color, add mustard seeds and red chiles. When the mustard seeds pop and the chiles darken -- a matter of seconds -- add carrots, ginger, and 1/2 teaspoon salt. Mix well, then add 4 tablespoons water. Cover and cook over low heat until carrots are tender, 3 to 6 minutes. Add coconut and cilantro; mix well. Serve immediately.