Put the sliced steak into a mixing bowl and add the soy, sugar, garlic, spring onions, kiwi fruit, gochujang ( if using) and sesame oil. Cover the bowl and refrigerate for the day. When you are ready to cook take the bowl from the fridge.
Put the rice into a sieve and wash under cold water for at least a minute until the water runs clear. Put the rice in a medium saucepan with 330 ml water and bring to a boil.
Reduce to a simmer and cook for 9 minutes then cover the pan, remove from the heat and leave to stand for 25 minutes without removing the lid.
When the rice is almost ready heat a large deep sided frying pan over a high heat. When the pan is hot add the sunflower oil and allow it to get so hot that it shimmers. Add the onion and stir fry for a few minutes until it softens and colours.
Add the beef and fry for a couple of minutes per side, without stirring until the beef has started to colour. Cook for as long as you prefer.
Serve mounds of stick rice topped with the beef and finished with a scattering of sesame seeds and some sliced spring onions.