Meanwhile, prep for the sauce.
Cut onions and capsicum in 3-cm squares, chop ginger and garlic finely, and cut green chillies and spring onions on the bias. Keep everything chopped and ready.
Make a sauce solution by mixing together dark soy, Green chilli sauce, vinegar, ketchup, red chilli sauce, salt, pepper, MSG and water in the proportions given in the 'For the sauce' section.
Keep this mixture ready as well.
Make a cornflour slurry using ½ tsp cornflour and 1 tsp water. Set aside.
Now, once the vegetables, sauce mixture and cornflour slurry are ready, heat up your wok.
Add vegetable oil and allow it to smoke.
Add dried red chillies, followed by onions and capsicum.
Fry on high heat for a minute before adding sugar.
Cook the sugar until slightly caramelised (1 minute).This will allow for the creation of the sticky sauce we've come to associate with chilli chicken.
Next, add ginger and green chillies, and fry for 30 seconds before adding garlic.
Then add the sauce solution.
When it comes to a boil, add the cornflour slurry.
Turn off the heat. We will come back to the sauce later.