Put the cooked pasta into the mixing bowl.
Put the skillet on the stove and turn the heat to medium.
After 1 minute, carefully add the canola or vegetable oil (the pan is hot and the oil might splatter). Add the sesame seeds – they will look like they're wiggling.
With the spoon, stir the sesame seeds in the oil until they are just beginning to turn brown.
Turn the heat off and remove the pan from the stove. Put the hot pan on a heat-safe surface. Add the garlic and ginger and stir until it turns golden brown.
Add the sesame oil, soy sauce, and water and mix well.
Add the peanut butter and hot chili sauce and mix well.
Pour the ingredients in the pan over the pasta and stir it with the spoon until the pasta is completely covered with the peanut sauce.
Sprinkle the scallions on top of the pasta and serve right away or cover and refrigerate up to 2 days.