For dressing: Juice 1 orange into a sealable container (a mason jar works well). Add sesame seeds, sesame oil, soy sauce, vinegar and 1/4 teaspoon pepper; mix well and set aside.
Dice mushrooms, slice onions, shred carrots and grate ginger; place into a medium bowl. Add soba noodles and half of the dressing; toss well and set aside.
Spray skillet with cooking spray and heat over medium. Drizzle grapeseed oil over salmon and season with remaining 1/2 teaspoon of pepper. Cook in skillet 3-4 minutes per side or until fish is opaque and flakes easily with a fork.
Serve soba noodles topped with salmon and drizzled with remaining dressing.