Prepare noodles as directed on packet. Drain, rinse under cold water, then drain well. Roughly cut into shorter lengths with kitchen scissors.
Heat a medium non-stick frying pan over a medium-high heat. Add salmon and cook for 3-4 minutes on each side (or cook in an air fryer at 180 °C for 8-10 minutes), until cooked to your liking. Transfer to a plate. Cool slightly, then break into small flakes.
To make dressing, whisk all ingredients in a small bowl until well combined
Combine noodles, salmon, carrot, cucumber, shallots and herbs in large bowl. Add half the dressing and toss to coat. Sprinkle with cashews. Drizzle over remaining dressing to serve.