In a mixing bowl, combine the chicken pieces with cornstarch, salt, and pepper. Toss to coat evenly.
In a large skillet or wok, heat the olive oil or sesame oil over medium-high heat. Add the chicken in a single layer and cook for about 4-5 minutes, stirring occasionally, until cooked through and golden brown.
While the chicken is cooking, whisk together the soy sauce, honey, sriracha, ginger, garlic, and sesame oil (if using) in a small bowl.
Once the chicken is cooked, pour the sauce over it in the skillet. Stir well to coat the chicken evenly in the sauce. Cook for an additional 2-3 minutes to thicken the sauce slightly.
Sprinkle sesame seeds over the chicken and stir to combine. Cook for another minute to toast the seeds lightly.
Serve the sesame chicken over cooked white rice, garnished with chopped spring onions. Enjoy!