Preheat the oven to 200˚C. Slice the capsicum and onions into thin strips and place them in a resealable bag with the vegan chicken. Add in 1 tbsp of olive oil to the bag and shake to coat the vegetables and chicken. Then add the corn starch, chili powder, cumin and 1/2 a tsp of salt and knead the bag until everything is well coated. Place in the fridge for 15 minutes.
Slice the zucchinis in half (long ways) and use a spoon to scrape out the flesh in the middle (keep this for a soup or stir fry). Drizzle 1 tbsp of olive oil over the zucchinis and season with salt and pepper. Bake for 20 minutes.
Heat 1 tbsp of olive oil in a frying pan over high heat, add the chicken and vegetable mixture and fry for around 6 minutes, stirring constantly, until the vegetables and chicken are cooked. The capsicum should still be a little crisp.
Once the zucchinis are cooked, remove them from the oven and spoon the chicken fajita mix into them. Sprinkle over some vegan cheese if you are using it and place back in the oven for 5 minutes to melt the cheese.