Preheat the oven to 180°C.
Using a sharp knife, score the top of each salmon fillet (about 5 mm deep).
In a small bowl, stir the miso paste, maple syrup and 2 tablespoons of hot water together into a smooth sauce. Pour over the fish.
Heat a seasoned grill pan and line it with a sheet of baking paper. Cook the salmon for 2 minutes on each side. Reserve the remaining marinade. Transfer the salmon onto a baking tray and place in the oven and cook for another 10 minutes.
Meanwhile, heat a wok to hot. Add the sesame oil and the mushrooms, and cook for 2 minutes. Wash the broccolini and bok choy and toss them into the wok with the mushrooms. Remove the wok from the heat while the greens are still crisp and drain off any excess liquid. Pour the reserved marinade over the vegetables.
Transfer the salmon to 2 serving plates and sprinkle with the sesame seeds. Serve over the Asian greens.