Whisk together the marinade ingredients in a small bowl and pour over lamb loin chops. Cover and refrigerate overnight or at least 4 hours. The longer the better. I usually do this in a large Ziploc bag and turn occasionally while marinating.
Roast a red bell pepper over an open flame or grill and when blackened place in a brown bag and close tight. Allow to steam for 20 minutes and remove stem, seeds and charred skin. Purée in a blender with 1 tsp of vegetable oil and pinch of kosher salt.
Preheat grill to 400° F. Remove lamb loin chops from marinade and grill to your liking. Drizzle the red pepper sauce over the cooked lamb loin chops, sprinkle with chopped cilantro and serve immediately.