1. In a bowl, whisk together the soy sauce, honey, minced garlic, grated ginger, rice vinegar, sesame oil, and black pepper.
2. Place the chicken thighs in a resealable bag or shallow dish and pour the marinade over them. Seal or cover and marinate in the refrigerator for at least 30 minutes (or up to overnight).
3. Preheat the oven to 400°F (200°C).
4. Remove chicken from the marinade and place it on a baking sheet lined with parchment paper. Reserve the marinade.
5. Bake chicken thighs in the preheated oven for 25-30 minutes or until they reach an internal temperature of 165°F (75°C), basting with the reserved marinade halfway through.
6. Once done, let rest for a few minutes before serving.
7. Garnish with sliced green onions before serving.