Preheat the oven to 200C/180C Fan/Gas 6
To make the marinade, mix together the ginger, garlic, soy sauce and sake in a bowl.
Score both sides of the duck in a criss-cross pattern, being careful not to cut through the meat. Add the duck to the marinade, cover and marinate in the fridge for at least 30 mins.
Drain any excess liquid from the duck, reserving the marinade.
Heat at least 1cm/½ in of vegetable oil in a wok placed over a high heat. Fry the duck skin-side down for 5 minutes or until the skin is crisp.
Place the duck flesh-side down into a roasting tin and finish in the oven for 30–35 minutes, or until well done, increasing the heat up to 220C/200C Fan/Gas 7 for the last 10 minutes. Allow to rest for 5 minutes.
Wash the sushi rice well until the water runs clear.
Fill a saucepan with 500ml/18fl oz water and bring to the boil. Place a bamboo steamer over the pan and add the rice. Put the on, turn the heat down to low and allow the rice steam cook for 15 minutes.
Mix together the mirin, rice wine vinegar and sugar. Fluff up the rice with a fork, pour the dressing over and stir well.
Just before serving, coat the duck in the flour mix and shake off any excess. Coat in the flour once again.
Preheat a deep-fat fryer to 180C. (CAUTION: hot oil can be dangerous. Do not leave unattended.) Deep-fry the duck for 2 minutes or until golden brown.
Drain the duck on a plate lined with a kitchen paper.
To serve, line the plate with shiso leaves. Add a mound of steamed sushi rice.
Place the duck legs on top on and garnish with garnish with black sesame seeds, shichimi pepper flakes and micro coriander leaves.
Serve with lime wedges an daikon spirals.