Prepare the Teriyaki Sauce by whisking together the finely chopped small onion, minced garlic, honey, low sodium soy sauce, rice wine vinegar, and grated ginger until well combined.

Cut the beef boneless eye of round roast in half lengthwise and place in the slow cooker. Pour the teriyaki sauce over the beef.

Cover and cook on high for 6-7 hours or low for 8-9 hours until the beef is fork-tender.

To thicken the sauce, mix cornstarch with a couple of tablespoons of water until smooth, then add it to the slow cooker and cook for an additional 10-15 minutes.

Shred the cooked beef into bite-sized pieces and mix it with the thickened sauce.

Prepare the lettuce cups by rinsing and drying the leaves, then arrange them on a serving platter.

Spoon the beef mixture into each lettuce cup and garnish with chopped green onions and sesame seeds.