Mix all marinade ingredients together and pour over lamb. Cover and marinate overnight in the refrigerator.
Remove lamb from marinade. Stud with garlic cloves and rosemary leaves.
Season with Hawaiian sea salt and freshly ground black pepper. Grill to medium-rare, (130 degrees F internal temperature registers on an instant-read thermometer), over kiawe wood coals. Let rest 10 minutes before slicing.
In a small saucepot add the vinegar and sugar. Cook over medium heat until the sugar dissolves and begins to turn light brown. Add wine and cook down, reducing by half. Add the remaining ingredients and half the mint. Simmer 10 minutes to let flavors marry. Adjust seasonings with salt and pepper. Stir in remaining mint just before serving.
Slice the lamb thinly across the grain. On a platter, fan the lamb over grilled vegetables and grilled mango. Top the lamb with some of the sauce. Garnish with crumbled Feta cheese and mint sprigs.