In a large pot, boil the lentils in 2 cups water for about 15 minutes or until tender. In the meantime, in a frying pan, cook onion in olive oil until soft, then add the beef and cook until it browns. Pour the onions and meat into the pot. Add tomato paste, pepper flakes, paprika, salt and pepper, bulgur and 6 cups of water. Cook until the bulgur is soft, about 20-25 minutes.