In a mixing bowl, combine white sugar, brown sugar, soy sauce, cider vinegar, minced garlic, ginger paste, and ground black pepper. Stir until fully dissolved and well blended.

Place the beef stew meat into your crock pot and pour the teriyaki sauce over it, ensuring each piece is well coated.

Cover and cook on low for approximately 6 hours, or on high for 3 hours.

30 minutes before serving, create a slurry by mixing cornstarch and water in a small bowl and stir into the sauce in the crock pot.

Once cooking is complete, stir gently and serve over rice, garnished with green onions and sesame seeds.