Remove the fresh rice noodles from the package and cut them into 1 ½ inch wide strips. If they were refrigerated, let them come up to room temperature and loosen them in some hot water.
If you are using dried rice noodles, follow the directions on the package to cook them. You can also soak them in hot water until softened and re-hydrated––about 15 to 20 minutes. Drain thoroughly. There should be no visual moisture on the noodles.
In a small bowl, dissolve the brown sugar in the hot water. Mix in the fish sauce (if using) and soy sauces. Set aside.
Heat your wok until smoking, and spread 2 tablespoons canola oil around the perimeter of the wok.
Add scallion whites and garlic and Thai basil (optional) if you have some. After 10 seconds, add the softened noodles. Your wok should be screaming hot now. Continue to toss the rice noodles for 30 seconds to warm them up. Next, stir up your soy sauce mixture and pour it over the noodles.
Continue stir-frying for 1 minute until the noodles are well coated. They should get a good smoky sear on them.
Next, add the mung bean sprouts and green portions of the scallions. Stir-fry for 1 minute, until the bean sprouts and scallions are wilted. Plate and serve with your favorite hot chili oil.