Method
Put the tuna steaks into a plastic sandwich bag, and pour in teriyaki sauce, soy sauce, garlic, chilli, coriander and half the sesame oil. Using your hands (outside the bag) distribute the mixture rubbing it into the steaks. Seal the bag and leave to marinate.
To make the tequenos, place flour and salt in a bowl. Add butter in ½ inch pieces along with the egg. Rub in until mixture is floury and crumbly. Add water a tablespoon at a time until the mixture start s to form a dough. Knead the dough. Cover and leave to rest.
Cut the cheese into 3–4 inch long sticks about ½ inch wide. Roll the dough out with a pasta machine; use the tagliatelle cutter. Use a strip of dough to wrap round each stick in a spiral fashion. The cheese should be completely wrapped.
Prepare the salad by layering the mango cubes with the avocado and drizzling on lime juice and a small amount of remaining sesame oil. Garnish with dill.
Heat the remaining sesame oil over a high flame in a wide pan. Coat the tuna steaks with the sesame seeds and cook for a minute on each side. Once seared, put a knob of butter on each of the steaks and finish off in the oven at 180ºC.
Cover the bottom of a heavy, high–sided skillet with vegetable oil and heat over a medium heat. Cook the cheese sticks in batches until all sides are golden brown (can also use a deep–fat fryer if preferred).
Remove steaks from the oven and transfer to plates beside the salad, drizzle with a little more teriyaki sauce and serve immediately with the cheese sticks.