Wash the lentils, peas, or beans in several changes of cold water. In a medium pot, cover them with the water and add the whole dried chiles, turmeric, and salt. Bring to a boil, reduce the heat, and simmer, stirring often, until very tender. This will take about 30 min. For red lentils, 45 min. For peas, or an hour or more for mung beans. It may be necessary to add more water to prevent sticking, but only 1/2 cup at a time, because the final consistency should be fairly thick. Use a heat diffuser if necessary.
When the lentils are almost cooked, heat the ghee or oil in a small pan, add the cumin seeds, and cook for 10 or 15 seconds. Stir in the onions and ginger and cook until the onions begin to brown, about 5 or 10 min.
When the lentils are tneder, remove and discard the hot peppers. Stir in the onion mixture, lemon juice, garam masala, and salt to taste. Serve, passing additional garam masala to sprinkle on top, if desired.
Spinach dal: Add 4 cups of chopped, fresh spinach to the onions after they have sauteed for about 5 min. And then cook for 5 min. More. Tomato dal: Add 1 cup chopped tomatoes to the onions after they have sauteed for about 5 min. And then cook for 5 min. More. Spinach-tomato dal: Add both spinach and tomatoes.