Put lentils & rice in separate pots. Pour enough boiling water over the lentils to cover them. Add 1.5 c boiling water to rice. Simmer both pots, covered, over low heat for 20 minutes. Drain & combine in one large pot. Add salt & another half c water. Cover & simmer 15 to 20 minutes until both rice & lentils are tender.
Meanwhile, fry the onions in oil until golden. Stir them into the rice before serving.