Place rice and 625ml water in a saucepan, season with 1 tsp salt flakes, bring to a simmer and cook, covered, for 15 minutes or until all liquid is absorbed. Remove from the heat and set aside for 5 minutes, then cool completely with the lid off. Stir through vinegar and furikake.
Line 2 baking trays with baking paper. Grease a piece of plastic wrap or foil.
Place ¼ cup firmly packed rice in the centre of the plastic wrap or foil, then bring the sides together and form a compact disc, about the same size as the ¼ cup measure. Transfer to one prepared tray. Repeat to make 12 onigiri. Chill until required, to remain firm.
For the salmon, preheat oven grill to high. Combine the miso, soy sauce and sugar in a bowl. Toss salmon in the miso mixture, then place on second prepared tray and grill for 3-4 minutes until golden brown and the salmon is just cooked through. Remove and set aside to rest.
Meanwhile, heat oil in a large non-stick frypan over medium high heat. In batches, cook the onigiri on their flat sides for 3-4 minutes each side until dark golden and crisp.
For the dipping sauce, combine all ingredients in a bowl.
Divide onigiri and salmon among plates. Scatter with herbs and extra furikake.
Serve with dipping sauce, Kewpie, sriracha and pickled ginger alongside.
