Fresh Chinese noodles are sold at most Asian markets; however, you can substitute your favorite dried spaghetti-type pasta and cook according to package directions. Dried pasta cooks more slowly than the fresh, so adjust preparation time. Be sure to trim off and discard the tough ends of the bok choy. For variety, use other leafy Asian greens, such as napa, choy sum or Chinese broccoli, or vegetables, such as bean sprouts or Chinese snow peas.
1. Bring pot of water to a boil over medium-high heat and when at a rolling boil, add fresh noodles. Cook for about 3 minutes, drain in colander, and rinse well under cold water. Set aside to continue draining.
2. Heat oil in wok over medium-high heat and stir-fry garlic and ginger until golden, about 2 minutes. Remove from wok and set aside.
3. Add tofu (and more oil as necessary), and stir-fry for 3 to 4 minutes, or until golden. Remove from wok.
4. Add scallions and stir-fry for 2 minutes. Add bok choy (and more oil as necessary), and stir-fry for 2 minutes, or until tender; add watercress and stir-fry for 2 minutes. Return garlic, ginger and tofu to wok and stir-fry 1 minute more. Remove from heat.
5. To make dressing, combine all ingredients in small bowl and mix well.
6. Place noodles in large serving bowl and toss with half of dressing. Add tofu and vegetables and toss with remaining dressing. Garnish with fresh coriander leaves and serve.