Mix the lamb with the oyster sauce and sesame oil. Reconstitute the noodles according to the packet instructions. Mix all the dressing ingredients together. Set aside.
Heat a wok or large pan. Add a tablesp. oil. Stir-fry the peppers and scallions for a minute or two. Remove from the wok. Stir-fry the lamb in two batches, keep warm. Add back the peppers and scallions plus the noodles and stir-fry for a few minutes.