Follow these step-by-step instructions carefully to achieve the perfect balance of flavors and textures. The key is to have all your ingredients prepped and ready to go (a concept known as mise en place) before you start cooking, as the process moves quickly.

1. Prepare the Teriyaki Sauce: In a medium-sized bowl, whisk together the low-sodium soy sauce, water, honey, mirin, toasted sesame oil, minced garlic, and grated ginger. In a separate, small bowl, whisk the 1 tablespoon of cornstarch with 2 tablespoons of cold water until it’s completely smooth and free of lumps. This is your cornstarch slurry. Set both the sauce mixture and the slurry aside for later.
2. Season and Sear the Chicken: Pat your chicken pieces dry with a paper towel; this is crucial for getting a beautiful golden-brown sear. Season them lightly with the black pepper and a small pinch of salt. Heat the avocado oil in a large skillet, wok, or cast-iron pan over medium-high heat. Once the oil is shimmering hot, carefully add the chicken pieces in a single layer. Do not overcrowd the pan; cook in two batches if necessary. Let the chicken cook undisturbed for 3-4 minutes per side, until it’s golden brown and cooked through. Remove the seared chicken from the skillet and set it aside on a plate.
3. Cook the Green Beans: To the same skillet, add the trimmed green beans. There should be enough residual oil and chicken fat in the pan, but if it looks dry, you can add another teaspoon of oil. Sauté the green beans for 4-5 minutes, stirring occasionally. You want them to become bright green and slightly tender, but still have a noticeable crunch.
4. Combine and Glaze: Reduce the heat to medium-low. Return the cooked chicken to the skillet with the green beans. Give the teriyaki sauce mixture a quick stir (as the ginger and garlic may have settled) and pour it into the skillet. Let it bubble gently for about 1-2 minutes, allowing the flavors to meld and coat the chicken and beans.
5. Thicken the Sauce: Now, give your cornstarch slurry another quick whisk to ensure it’s combined, and slowly pour it into the skillet while constantly stirring. Continue to stir and cook for another 1-2 minutes. You will see the sauce magically transform, thickening into a rich, glossy glaze that clings beautifully to every piece of chicken and every green bean.
6. Final Touches and Serving: Once the sauce has thickened to your liking, remove the skillet from the heat. If using, sprinkle generously with toasted sesame seeds and sliced green onions. Serve immediately while hot for the best experience.