Prepare the marinade: In a bowl, whisk together soy sauce, honey, rice vinegar, sesame oil, garlic, and ginger.
Marinate: Place the pork tenderloin in a resealable bag. Pour in the marinade, seal, and refrigerate for at least 30 minutes.
Preheat oven or grill: Set the oven to 400°F (200°C) or preheat the grill to medium-high heat.
Bake or grill: Remove pork from the marinade, reserving the liquid. Roast for 25 minutes or grill for 20 minutes, turning occasionally.
Thicken the glaze (optional): Simmer the reserved marinade with cornstarch until thickened.
Glaze the pork: Brush the thickened sauce over the cooked tenderloin for an extra punch of flavor.
Rest and slice: Let the pork rest for 5 minutes before slicing. Garnish with sesame seeds and green onions.