Coat the chicken: Add the chicken pieces, salt, pepper, and cornstarch to a medium bowl. Toss until every piece is evenly coated.
Prepare the sauce: In a small bowl, whisk together the soy sauce, honey, sriracha, garlic, ginger, rice vinegar, and red pepper flakes.
Sear the chicken: Heat a large cast-iron or stainless-steel skillet over medium-high heat. Add the olive oil and swirl to coat the pan. Arrange the chicken in a single layer and cook undisturbed for 4–5 minutes, until golden and crispy on one side.
Finish cooking: Reduce the heat to medium. Turn the chicken pieces and cook for another 1–2 minutes, stirring occasionally, until browned on all sides and cooked through.
Add the sauce: Pour the prepared sauce over the chicken. Cook for 3–5 minutes, stirring frequently, until the sauce bubbles, thickens, and forms a glossy sticky glaze around the chicken.
Garnish and serve: Remove the skillet from the heat. Sprinkle with toasted sesame seeds and chopped green onions. Serve warm with rice, noodles, or steamed vegetables.