01 - In a medium bowl, whisk together soy sauce, brown sugar, water, rice vinegar, sesame oil, ginger, garlic, gochujang, and toasted sesame seeds until smooth.
02 - Place beef chunks in the slow cooker. Pour sauce over the beef, turning to coat evenly.
03 - Scatter half of the green onions over the beef.
04 - Cover and cook on low for 7 hours, or until beef is very tender and can be easily shredded with a fork.
05 - Shred the beef directly in the slow cooker using two forks. Stir to coat with the sauce.
06 - Serve hot over steamed rice, in lettuce wraps, or with steamed vegetables. Garnish with remaining green onions, sesame seeds, and optional sliced red chili.