Linguine is a good substitute for udon.

12 oz udon noodles or linguine
2 T toasted (dark) sesame oil, divided
1/2 c tahini
3 T soy sauce (tamari or shoyu)
1/4 c water or broth
1 T lemon juice
1 T vegetable oil
1 bunch choi, thinly sliced crosswise
2 scallions, minced
1 t fresh, peeled ginger, minced
2 T toasted sesame seeds

1. Cook noodles according to package directions and personal preference. Drain and place in a bowl. Add 1 T of the dark sesame oil and toss to coat. Set aside.

2. In a small bowl, combine the tahini, soy sauce, water or broth, and lemon juice until well blended.

3. Heat the vegetable oil over medium heat in a skillet that can hold all the ingredients. Add the choi, scallions, and ginger and stir-fry until the choi is wilted and becoming tender. Add some water if the mixture is sticking to the pan. When the choi is done to your liking, stir in the tahini sauce and noodles and combine. Cook, stirring, until heated through, 2 or 3 mintues.

4. Drizzle with the remaining 1 T of dark sesame oil and serve, sprinkled with the toasted sesame seeds.