Cook noodles according to package directions; drain, reserving 1 tablespoon pasta water. Keep noodles warm.
Heat canola oil in a large nonstick skillet over medium-high heat. Add ginger and garlic; sauté 30 seconds. Add onion and bell pepper; cook 3 minutes or until golden brown, stirring often. Add mushrooms, salt, and reserved 1 tablespoon pasta water; cook 2 minutes or until mushrooms are tender, stirring frequently. Stir in snow peas, and cook 1 minute.
Combine mirin, soy sauce, and sesame oil in a small bowl, stirring with a whisk. Add mirin mixture and noodles to pan; toss to combine. Serve immediately.