Add onion; cook 5 minutes or until tender, stirring occasionally.
Add lentils, ginger, pepper, and cinnamon; cook 10 minutes, stirring occasionally. Stir in 1 cup water and broth; bring to a boil. Reduce heat, and simmer 10 minutes.
Add remaining 1 cup water and juice, and cook 30 minutes or until thick, stirring occasionally. Stir in salt.