Bring water to a boil and add lentils or split moong dal; cover, reduce heat and simmer 12-15 minutes or until completely tender. Drain any excess water. In a small skillet, heat the ghee; add the onion and sauté until softened, about five minutes. Add the ginger, garlic and spices and cook for a minute or two, stirring occasionally. Add the tomato and salt to taste and simmer a few minutes to blend flavors. Stir the onion-spice mixture into the cooked lentils and serve over hot rice or with flatbread.