Create a "sling" by crossing two large sheets of heavy-duty aluminum foil in the bottom of your slow cooker.
Place the beef medallions inside the foil sling in a single layer.
In a bowl, whisk together soy sauce, honey, brown sugar, minced garlic, ginger, and apple cider vinegar.
Pour evenly over the beef.
Fold the edges of the foil up slightly to create a shallow bowl, keeping the sauce around the meat.
Cover and cook on Low for 4-5 hours until the beef is incredibly tender.
Carefully open the foil, sprinkle with sesame seeds and green onions, and serve with the rich pan juices!
