Cook ramen noodles according to package directions, but do not add seasoning packets to pan. Drain noodles, and place in serving bowl. Dissolve 1 packet of ramen flavoring in 1-3/4 cups water, then discard remaining packet. Add teriyaki sauce to seasoned water, and set aside.
In large nonstick skillet, heat oil over medium-high heat. Add ginger, and cook 30 seconds. Stir in seasoned water; bring to a boil. Add vegetables, and cook 3 minutes.
Dissolve cornstarch in water, whisk into boiling sauce, and cook 1 minute more. Add shrimp, toss to coat with sauce, and heat through. Pour over hot noodles, and toss. Sprinkle with green onions, if using.