Combine the marinade ingredients and mix well. Pour marinade into a large flat glass or ceramic dish. Add the lamb, turning to coat all sides. Marinate in the refrigerator, meat side down, for 2-3 hours or overnight.
To make orzo salad, cook pasta according to directions on packet and drain well.
While allowing orzo to cool slightly, cut the kernels from the fresh corn. Combine pasta, corn, juice, zest and remaining ingredients in a large bowl, toss well and season with salt and pepper to taste.
Remove the meat from the marinade and pat dry. Place the marinade in a small pan and bring to a boil. It is important that the mixture comes to a rapid boil. Reduce heat and simmer until liquid starts to thicken slightly and become glossy. Keep warm.
Heat grill to medium high, and cook the lamb racks for 5-6 minutes each side for medium-rare, or as desired. Allow to rest for 5 minutes.
Spoon orzo salad onto a large platter and place whole racks on top, or separate lamb into 3-4 chop portions and serve on individual plates. Spoon glaze over and serve with a green salad.
