Heat up sesame oil in frying pan or wok. (Cast iron is my favorite for making Chinese food).
Add cut up meat and brown on both sides. If the pan is hot it will take two-three minutes per side. The meat cooks fast.
Add the onions, red and green peppers. Stir until vegetables soften. An additional 2-3 minutes. I like a crispness to the vegetables and I don't want to kill all the nutrients.
Sprinkle on the salt and pepper. Stir in the tamari.
Cook for an additional minute while stirring to make sure everything is well coated.
This goes well on top of cauliflower rice.