In medium bowl add the oil, hoisin, soy sauce, maple syrup, garlic, ginger and 5 spice powder. Season and stir to combine. Place the lamb ribs in a large snap lock bag or glass container, add the marinade and rub to coat. Marinate at room temperature for 30 minutes.
Preheat a barbecue or char-grill pan to medium heat. Drain ribs, reserving marinade. Add the ribs and cook until browned and charred on all sides, turning regularly to prevent burning, for 15 to 20 minutes, or until cooked through. Set aside covered with foil to rest for 5 minutes.
Heat the reserved marinade and 1/3 cup (80ml) water in a small saucepan over medium-low heat for 4 to 5 minutes until slightly thickened and heated through.
Serve ribs drizzled with marinade, sprinkled with chilli, green onions and sesame seeds with Asian greens and rice on the side.
If using riblets/single ribs they will only take about 10-15 minutes.
Substitute marinade with a premade char sui marinade to save time.