Soak 8 wooden skewers in cold water and set them aside.
Cut the red onion, peppers and courgette into chunks
Trim and slice the steak into 1 inch pieces
For the marinade:
Pour the oyster sauce, and soy sauce into a mixing bowl, add the steak and mix, cover with cling film and marinate for 20 minutes.
To cook the steak:
Preheat a char-grill or barbecue to high. Thread the meat and vegetables onto the soaked skewers and grill for 1 - 2 minutes on all sides, keep turning the kebabs. Sprinkle with salt and chilli seasoning and continue to cook for a further 30 seconds on all sides.
Remove from the grill and place on a warm serving plate. Cover with tin foil and rest for 5 minutes.
Serve with any of the following: steamed rice, baked potatoes, wedges, noodles, flatbreads or vegetables.