Cook the quinoa according to the packet instruction, then drain.
Meanwhile, turn on the oven, setting the temperature to 180°C.
Finely chop the onion and garlic.
Heat a spoonful of olive oil in a frying pan and gently sauté the onion and garlic ( you can add some chilli too if you like it hot). This should take about 5-8 minutes. Add the chipotle paste and tomatoes ( or tomato purée), stir for one minute.
Put the drained quinoa in a mixing bowl and add the spiced onion mixture.
Rinse and drain the beans and corn, add these to the mixture. Season to taste, then add the feta (crumbled) and the chopped coriander leaves. Toss gently, taste and adjust the heat and seasoning to your liking.
Halve the peppers lengthways and remove the seeds.
Oil a baking tray. Stuff the pepper halves with the mixture and place them carefully in the tray.
Bake them for 15-20 minute until the pepper is tender.