Set rice to cook according to the package instructions.
*TIP: too keep rice fluffy, do not stir while it’s cooking. Stirring rice releases starches and makes rice sticky.
Chop and slice vegetables so it's ready when starting to cook.
Whisk all ingredients for the sauce and set aside.
Slice chicken meat into small pieces and combine it in a bowl with some salt and cornstarch. Make sure that cornstarch is spread evenly throughout.
Preheat a large cooking pan over medium heat and add oil. Saute chicken until almost done, take chicken (and juices) out of the pan, and set it aside.
Add a little bit more peanut oil to the pan if needed. Add minced garlic and grated ginger and saute just until it's fragrant.
Add remaining vegetables to the pan, stir, and saute until starts to soften.
When vegetables start to soften, add chicken back in, and add the sauce. (Make sure to quickly whisk the sauce mixture before adding it because cornstarch settles to the bottom.)
Cook everything, while stirring slowly, until sauce thickens and vegetables are as soft as you like it.
Add cooked rice to the chicken and vegetables pan and carefully mix everything together until evenly combined. Top off with some sesame seeds and scallions of you wish and serve.
NOTE: if using pre-cooked teriyaki sauce, you don't need to wait until it's thickened. Simply cook everything together for a couple of minutes and then add rice.