Mix together the oil, chilli sauce, ketchup, sugar, garlic and chilli's with a little salt and pepper. Marinate the beef strips for at least 1 hour in the mix, but preferably overnight.
Put the rice on to cook according to packet instructions.
Using tongs, pull the strips of beef out of the marinade and add to a hot wok. Stir fry for 2 minutes. In a separate pan, stir fry the onion and peppers, and add to the beef after it's cooked for 2 mins.
Add the sauce to the beef and vegetables, stiry fry for a further 2 minutes then serve on rice whilst steaming hot!
You can sprinkle with some roasted cashew nuts for an extra dimension.