Select 4 to 6 outer radicchio leaves that form a natural cup and set aside. Cut the remaining radicchio head into strips, you should have about 1 1/2 cups.
Mix the lamb with the onion, garlic, ginger, chili flakes, hoisin sauce and salt and pepper, to taste. Heat a wok or large skillet over high heat. When really hot, add the peanut oil, and stir-fry the lamb until it is cooked. Add the plum wine and red bell pepper, and cook for another minute or two. Adjust seasoning, if necessary.
Fill radicchio cups equally with radicchio strips. Spoon the lamb mixture into the cups and garnish with fresh mint leaves.