Heat the oil in a large frying pan, and add the grated squash, onion and garlic. Cook over a medium-low heat, stirring only occasionally. You can add a touch of sugar to help the caramelisation process if you want to.
While the squash is cooking, boil the quinoa in a pan of water until it is soft and the spiral-shaped germ has become detached. Drain, and set aside.
Continue to cook the squash, not stirring too often, until it caramelises and begins to turn golden brown (around 30 minutes in total). When it's ready, add the cooked quinoa and season well. Mix to combine.
Serve the mixture wrapped in flour tortillas with fresh spinach and plenty of fresh coriander.