In a small bowl or liquid measuring cup, add the soy sauce, rice wine vinegar, brown sugar, garlic, and cornstarch. Whisk to combine. Set aside.
Heat a wok or large skillet with 3 inches (7 cm) of oil to 400˚F (200˚C).
Pull the rice noodles apart into eight portions.
Place one portion of noodles on a slotted spoon and carefully dip into the oil. The noodles will immediately fry. Once puffed up, remove the noodles and transfer to a wire rack to drain. Repeat with the remaining noodles.
Season the chicken with salt and pepper.
Heat a wok or large skillet with 1 tablespoon of oil over medium-high heat. Once the oil begins to shimmer, add the chicken and cook, stirring occasionally, until browned and cooked through, about 5 minutes.
Add the teriyaki sauce to the chicken and bring to a boil. Cook until the sauce has reduced by one third and the chicken is fully coated.
Serve the chicken over the rice noodles with snap peas, radish slices, scallions, cilantro, and sesame seeds.