Sprinkle the tuna on both sides with the
salt. Then sprinkle with the black pepper, pressing to adhere.
Heat the vegetable oil in a large frying
pan over moderate heat. Add the tuna and sear for 2 minutes on both sides for
medium rare. Remove from the pan and set aside.
Reduce the heat and add the sesame oil,
ginger, garlic and scallions. Cook, stirring for 1 minute. In a small bowl,
combine the soy sauce and orange juice.
Add the orange juice mixture and simmer for
about 2 minutes. Plate the tuna and serve with the sauce.