Cut the zucchinis in half lengthwise and use a spoon to scoop out the centre and keep it for the stuffing. Make sure to leave about 1/2 inch of flesh all around to form a stuffable "boat".
Place the zucchinis in a tray with the cut side up and brush with a thin layer of olive oil. Place it under the grill until it starts to brown evenly, you might have to turn the tray multiple times to achieve this depending on your grill. Take out the zucchinis while they are still firm.
Meantime rinse your quinoa and bring the vegetable stock or water to a boil in a small sauce pan. Add the quinoa to the boiling stock, lower the heat and let simmer for about 15 minutes.
At the same time, heat some olive oil in a large pan and stir fry the zucchini centres, onions, pepper, kidney beans and corn kernels for a couple of minutes.
Add the garlic, cumin, oregano, tomato puree and chilli and mix to combine. Cover with a lid and let simmer for about 15 minutes.
Add the cooked quinoa, tomatoes, coriander and 1/2 of the vegan or cheddar cheese.
Fill the stuffing into the zucchini "boats" and sprinkle the leftover cheese on top.
Place the tray back under the grill until the cheese melts and starts to brown, keep an eye on it so that it won't burn.