For the noodles with pak choi, first mix the soy sauce with water, lemon juice, sugar, chili threads and cornstarch.
Wash pak choi and cut large leaves smaller. Cut garlic into thin slices.
Heat peanut oil in wok, add pak choi and stir-fry until collapsed (about 2 minutes).
Briefly stir-fry garlic and chili. Pour in soy sauce mixture and simmer for about 2 minutes.
Prepare noodles according to package directions. Sprinkle sesame seeds on a baking sheet and grill under supervision until seeds are brown.
Season pak choi sauce to taste, mix with noodles.
Serve the noodles with pak choi sprinkled with the sesame seeds.