Cut all the vegetables into very fine julienne.
Boil the egg noodles until they are 3 minutes short of fully cooked (check the package for exact timing).
Heat oil in a wok or large skillet over high heat. Stir-fry the vegetables (except the asparagus) for 2 minutes.
Add the asparagus and cook for another 30 seconds.
Add the noodles straight from the pot into the wok. Mix well.
Add the sauce: mostly light soy sauce, with just a splash of dark soy sauce and black vinegar (if using). Stir-fry for 30 seconds.
Add the sweet chili sauce and stir-fry another 30 seconds.
Important: Add one ladle of the noodle cooking water.
Continue stir-frying until the sauce reaches the desired consistency (about 30 seconds more).
Finish with finely chopped scallions and lime zest.
Enjoy!