Combine the wasabi, soy sauce, mirin and ginger in a small bowl. Pour half the mixture into a shallow glass or ceramic dish, add salmon and stir to coat (reserve remaining mixture). Cover and place in the fridge for 1 hour to marinate.
Preheat a chargrill pan over high heat and spray lightly with oil. Grill the salmon for 2-3 minutes each side for medium or until cooked to your liking. Set aside to cool slightly, then flake the salmon.
Meanwhile, heat 3 tsp oil in a large non-stick frying pan over high heat. Cook mushroom, stirring, for 3 minutes or until golden. Transfer to a bowl. Set aside.
Heat the remaining 1 tsp oil in the frying pan. Add capsicum and garlic and cook, stirring, for 2 minutes or until just tender. Add the kale and cook, stirring, until the kale is just wilted. Remove from heat.
Cook the noodles in a saucepan of boiling water following the packet directions or until al dente. Drain. Divide the noodles, mushroom, kale mixture and salmon among bowls. Drizzle with the reserved marinade and sprinkle with the coriander.