Place the rice, quinoa and 2 cups (500ml) cold water in a saucepan over high heat. Bring to the boil, stirring occasionally. Reduce heat to low. Cover and simmer for 10 mins or until liquid is absorbed. Set aside, covered, for 10 mins or until tender.
Meanwhile, place stock and chicken in a deep frying pan and add water to cover. Slowly bring to a simmer over medium heat. Cover and set aside for 5 mins or until chicken is cooked through. Transfer chicken to a plate and shred. Cover with foil to keep warm.
Heat the poaching liquid in the pan over medium heat. Add soy sauce, mirin and sugar. Simmer for 2 mins or until liquid reduces slightly.
While the broth is cooking, heat a non-stick frying pan over high heat. Spray with olive oil spray. Pour in the egg and swirl to coat the base. Cook for 2 mins or until just set. Turn onto a clean work surface. Roll the omelette into a log and thinly slice into ribbons.
Divide the rice mixture among serving bowls. Top with wombok, carrot, broth, chicken, omelette and spring onion.