- Combine first 4 ingredients in small bowl, stirring until blended. Set aside.
- Snap off tough ends of asparagus. Remove scales from stalks with a knife.
- Cut asparagus diagonally into 1½" pieces. Set aside.
- Pour oil around top of preheated wok, coating sides; heat at medium high for 2 minutes.
- Add asparagus and green onions; stir-fry 3-4 minutes.
- Add mushrooms; stir-fry 1 minute.
- Add reserved cornstarch mixture to vegetable mixture in wok; cook until thickened and bubbly.
- Add tomato, and cook just until heated.
- Serve immediately.