Break up ramen noodles and cook according to package directions, omitting but reserving seasoning packet. Drain and keep warm.
In small saucepan, blend cornstarch, seasoning packet from noodles, water, reserved salmon liquid, soy sauce, sesame oil, garlic powder, and ginger. Cook over high heat, stirring frequently, until mixture boils; continue cooking for 1 minute. Remove from heat; reserve and keep warm.
In large saucepan, heat oil over medium-high heat. Add frozen stir-fry vegetables and water chestnuts or corn. Stir-fry 3 minutes. Add salmon; cover and cook 1 minute. Add noodles and sauce; stir gently and heat through.