Sprinkle the chicken with cornstarch and toss until every piece glistens. This helps it crisp and cling to the sauce later.
Heat oil in a skillet over medium-high heat. Add chicken in a single layer; cook until browned and cooked through, about 5–7 minutes. Don’t crowd the pan—work in batches if needed.
Remove chicken and set aside. In the same pan, add garlic and ginger; sauté 30 seconds until fragrant. Don’t burn them—the moment they turn charcoal, you’re in trouble.
Stir in soy sauce, rice vinegar, honey, hoisin (if using), sesame oil, and water. Bring to a simmer and let the glaze thicken a bit, about 2–3 minutes.
Return chicken to the pan. Toss to coat in the glossy sauce. Cook 1–2 minutes more so everything happily sticks together.
Finish with a shower of sesame seeds and green onions. If you’re feeling fancy, drizzle a tad more sesame oil on top.
Serve hot over rice or with steamed veggies. Bite, smile, repeat.