Cook the quinoa in salted boiling water as per the packet instructions, drain and set aside.
Add the diced avocado and mango to a bowl and squeeze over the juice of one lime. Set aside until ready to serve.
Heat 2tbsp olive oil over a medium in a non-stick frying pan and add the chorizo. Cook the chorizo for 5 minutes taking care to colour it but not burn. Add the spring onion and garlic and cook for a further minute. Stir through the prawns, chopped coriander and quinoa and gently keep warm. (If using uncooked prawns you will need to add them at the same time as the spring onion to allow them to cook through).
Meanwhile, over a medium heat melt the butter and further 2tbsp olive oil in a non-stick frying pan. Add the hake fillets and cook for 2 minutes on each side, or until cooked through (this will depend on the size of your fillet).
Place the quinoa salad on a warm plate and lay the hake fillet on top. Spoon over any chorizo oil that may be left in the pan. Serve immediately with the avocado and mango salsa.