Sort lentils and rinse under cold water. Cook lentils in 4 cups of cold water over medium heat 25 minutes. Add rice, salt, pepper, reduce heat to low, cover and cook 20 minutes more. Drain excess water. Set aside.
Saute onions in oil over medium-high heat until golden brown. Stir half the onions into lentil mixture, reserving remaining half as garnish. Pour lentil salad into a serving platter while hot and smooth over with the back of the spoon. Garnish sides of platter with lemon wedges to squeeze on top of each serving. Spoon remaining onions on top. Sprinkle parsley on top of the salad just before serving.