Soak rice stick in hot water for 5 minutes. Drain and set aside.
In medium frying pan or wok, heat 1 tablespoon peanut oil on medium-high heat. Saute garlic and chili flakes until garlic is golden. Remove from heat, pour into a bowl and set aside.
Place pan back on medium-high heat and add remaining 2 tablespoons peanut oil. Add vegetables and fry about 5 minutes, until broccoli is bright green and snow peas are just beginning to go limp. Add chicken, if using, and keep frying until chicken is just cooked through. Add noodles, then teriyaki sauce and stir mixture together until sauce is evenly distributed. Stir in garlic and chili flakes. Keep frying the mixture until most of the liquid is evaporated (I like to fry until the noodles start to stick to the bottom of the pan, but that means you will have some crusty noodles). Remove from heat and serve, garnishing generously with peanuts!