Cook noodles according to package directions, then rinse with cold water and set aside.
Thinly slice 1 pound of beef, making sure the slices are super thin, that way they cook really fast. (I used a meat thinner to make my slices very thin).
Place beef slices in a small bowl, add 2 tablespoons of corn starch and rub the slices with your hands until the meat absorbs the starch, set aside and let stand for about 5-10 minutes.
Heat 2 Tbsp of oil in a large skillet, fry your beef slices until golden brown.
While beef is frying, prepare the sauce. In a small bowl, mix together the soy sauce, sugar, minced garlic, sesame oil, rice vinegar, canola oil and couple tablespoons of hot water. Whisk until the ingredients are well blended.
Add the sauce into the skillet with fried beef and simmer on low for 10 minutes until the sauce slightly thickens and beef slices are tender.
Add cooked noodles into the skillet and mix until the sauce gets absorbed by the noodles. mix with green onion. Serve immediately.