Cook the noodles in a large pan of boiling salted water according to package instructions. Drain well. Keep them in a bowl of cold water until needed (to keep them from sticking together).
Meanwhile, cook broccoli for 2 minutes in pan of boiling salted water, then drain and refresh under cold water.
To make sauce, whisk soy sauce, tahini and cornstarch to a thick paste, then whisk in sesame oil, chile oil, vinegar, sugar and stock.
Heat vegetable oil in a large wok or skillet and stir-fry garlic and ginger for 1 minute, until it starts to color. Add pork and stir-fry over high heat, breaking it up with a wooden spoon, until it browns. Add sauce and allow to boil until it thickens, about 2 minutes.
Add drained noodles and broccoli, stirring them in well to make sure they are well coated with the sauce and heated through. Serve scattered with the green onions and peanuts.