Preheat oven to Gas Mark 6, 200°C (400°F).
To make the Cucumber Pickle: Place the rice wine vinegar, sugar and salt in a glass or ceramic bowl. Stir until the sugar dissolves. Add the cucumber and red onion. Toss to combine. Set aside for 2 hours, tossing every 30 minutes.
Meanwhile combine the miso paste, honey, soy sauce and rice wine vinegar. Line a roasting tin with non-stick baking paper and place the salmon, skin side down onto the paper. Brush all over with about three quarters of the miso mixture. Reserve the rest of the mixture to use later.
To cook the salmon: Place the roasting tin in the hot oven and cook the salmon for 10 minutes or until it is cooked to your liking. Preheat the grill to high. Brush the salmon with reserved miso mixture and grill for 5 minutes or until charred.
To serve: Sprinkle the salmon with the sesame seeds, scallions and coriander. Serve with the cucumber pickle, pickled ginger, wasabi mayonnaise and a green salad.