Heat a wok over medium high heat until hot. Swirl in the cooking oil. Add the ground beef and cook until browned, about 2 minutes. Add in the garlic and the green onions. Stir fry for 30 seconds. Then add in the red onion and the bell peppers. Stir to mix well. Stir in the Miso & Easy, the hot sauce and the oyster sauce. Let simmer for 2 minutes or until the beef is cooked through.
Use a slotted spoon to remove the meat mixture to a bowl. Fill each lettuce cup with the ground beef mixture. Top with slivered fresh chilies if desired.