Slice the beef fillet into thin strips about 5–6 cm (2–2½ inches) long. Place them in a dish and pour over the soy sauce, mixing well to make sure the beef is fully coated in the soy sauce. Cover closely and leave in the refrigerator while cooking the rice.
Prepare the rice: rinse it several times under cold running water until the water runs clear then drain in a sieve. Place the rice in a heavy-based saucepan. Add the water and seasoning. Bring to the boil, cover, lower the heat and cook for around 15 minutes. Remove the pan from the heat and let stand, covered, for about 10 minutes. Aerate the rice by stirring with chopsticks.
Heat the groundnut oil in a wok. Drop in the drained beef strips and stir-fry over a fairly high heat, then set aside and keep warm on the warming rack of the wok.
Stir-fry the onions in the wok. Add the strips of orange rind. Stir, then add the beef. Season and cook for 1 minute.
Serve immediately, accompanied with plain rice.