Prepare Marinade: In a small bowl, whisk together honey, soy sauce, sesame oil, minced garlic, rice vinegar, salt, and black pepper.
Marinate Chicken: Place the chicken thighs in a large zip-top bag or shallow dish. Pour the marinade over the chicken, ensuring all pieces are well-coated. Marinate in the refrigerator for at least 30 minutes, or up to 2 hours for deeper flavor.
Cook Chicken: Heat olive oil in a large skillet over medium-high heat. Remove the chicken from the marinade (reserve the marinade) and cook for about 5-7 minutes on each side, until fully cooked and caramelized. Remove from the skillet and set aside.
Thicken Sauce (optional): If you prefer a thicker sauce, mix the cornstarch with a little water to create a slurry. Add the reserved marinade to the skillet and bring to a simmer. Stir in the cornstarch slurry and cook until the sauce thickens, about 2-3 minutes.
Combine and Serve: Return the chicken thighs to the skillet, coating them with the sauce. Cook for an additional 1-2 minutes to ensure the chicken is well-coated and heated through. Garnish with sliced green onions and sesame seeds.