Whisk the soy sauce, sesame oil and pepper together in a shallow dish. Heat the sunflower oil in a non-stick frying pan. Sear the steaks on both sides until cooked to your liking. Transfer to the dish with the marinade, then chill for 1 hr. Turn the steaks, then continue to chill until ready to assemble.

Tip all the veg into a large serving bowl with both types of ginger and the nori. Drizzle over the mirin and lime juice, then add the coriander and chilli. Toss and rest for 20 mins.

Make the dressing by whisking everything together. To serve, slice the tuna and arrange over the salad, then sprinkle over the coriander seeds and drizzle over the dressing.