Heat the margarine in a frying pan and stir in the rice. Cook over medium heat, stirring often until rice is delicately golden. Sprinkle rice with salt. Mix in the onion, bologna, tomatoes, corn and water. Bring mixture to a vigorous boil, cover closely, reduce heat to simmering point (low heat) and without lifting lid cook for 14 minutes exactly. Remove from heat and let stand, still covered, for 10 minutes. Turn onto a platter and sprinkle generously with chopped parsley.