Preheat the grill to medium-high heat.
Season the pork tenderloin with salt and pepper.
In a small bowl, mix together the soy sauce, minced garlic, minced ginger, honey, and sesame oil.
Pour half of the marinade over the pork tenderloin and let it marinate in the fridge for 10-15 minutes.
In another small bowl, mix together the remaining marinade with the peanut butter and rice vinegar to make the peanut sauce.
Grill the pork tenderloin for about 10 minutes on each side, brushing with the marinade occasionally.
Once the pork is cooked through (internal temperature of 145°F), remove it from the grill and let it rest for 5 minutes.
Slice the pork and serve with the peanut sauce on the side.
Garnish with sesame seeds, if desired.