Rinse lentils thoroughly and place in a medium saucepan along with ginger, turmeric, salt and cayenne pepper. Cover with about 1 inch of water and bring to a boil. Skim off any foam that forms on top of the lentils. Reduce heat and simmer, stirring occasionally, until beans are tender and soupy.
Meanwhile, in a microwave safe dish combine oil, dried onion and cumin seeds. Microwave on high for 45 seconds to 1 minute; be sure to brown, but not burn, onions. Stir into lentil mixture.