Preheat the oven to 425°F.
In a large baking dish, whisk together the honey, soy sauce, vegetable oil, sesame oil (if using), vinegar, scallions, garlic, and ginger.
Trim off any visible fat from the chicken thighs, then season them on both sides with salt and pepper.
Place the chicken thighs in the baking dish, turn to coat them in the sauce, and press down to submerge them as much as possible, making sure they are in a single layer. (It's OK if they're crowded; just don't let them overlap too much.)
Transfer the baking dish to the middle rack of the oven. Roast for 10 minutes, use tongs to carefully flip the chicken thighs, and then roast for another 10 minutes or until the chicken registers 165°F on an instant-read thermometer.
Garnish with more sliced scallions and a splash of soy sauce, if desired, and serve the chicken and sauce over rice with steamed veggies.