In a large bowl, combine honey, soy sauce, rice vinegar, minced garlic, and grated ginger. Mix well to create the marinade.
Add the chicken thighs to the marinade, ensuring they are fully coated. Cover and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.
Heat vegetable oil in a large skillet over medium-high heat. Remove chicken from the marinade, allowing excess marinade to drip off, and season with salt and pepper.
Add the chicken to the skillet and cook for about 5-7 minutes on each side, or until golden brown and cooked through.
While the chicken cooks, pour the remaining marinade into a small saucepan. In a separate bowl, mix cornstarch and water until smooth, then add to the saucepan.
Bring the marinade to a simmer over medium heat, stirring constantly until it thickens, about 2-3 minutes.
Once the chicken is cooked, pour the thickened sauce over the chicken in the skillet. Toss to coat evenly and heat through for an additional 1-2 minutes.
Serve the sticky honey garlic chicken hot, garnished with chopped green onions and sesame seeds.