As accompaniments to this great-tasting main course, serve the Risotto-Style Barley with Spring Greens, and pour glasses of chilled Pinot Grigio.
Preheat oven to 325°F. Place garlic and wine in center of foil sheet. Sprinkle with salt and pepper. Enclose with foil; crimp edges to seal. Bake until garlic is very tender, about 50 minutes. Squeeze garlic between fingers to release cloves. Transfer garlic and any cooking liquid to blender.
Meanwhile, combine orange juice and reserved shrimp shells in heavy medium saucepan. Boil until liquid is reduced to 3/4 cup, about 10 minutes. Strain liquid into blender with garlic; discard shrimp shells. Puree until mixture is smooth. Cool marinade completely.
Mix shrimp and marinade in bowl. Cover; chill 1 1/2 hours. Drain marinade.
Thread 5 shrimp onto each skewer. Place parsley in shallow dish. Coat 1 side of each shrimp skewer with parsley.
Spray large nonstick skillet with nonstick spray. Place skillet over medium-high heat. Add 6 shrimp skewers to skillet, parsley side down; cook until shrimp are pink and just cooked through, about 1 1/2 minutes per side. Wipe out skillet, then spray with more nonstick spray. Repeat with remaining 6 shrimp skewers.
Spoon barley with greens onto plates. Top with shrimp and serve.