The universal appeal of shrimp scampi, frankly, isn’t the shrimp but the pan sauce: garlicky butter lightened with white wine and bursts of lemon, parsley and red-pepper flakes. Scampi is often tossed with pasta or served with crusty bread, but this version instead uses quick-cooking orzo. It simmers directly in the pan sauce, imparting a starchy gloss — and soaking up the garlicky scampi flavors. Toss the shrimp with some garlic, lemon zest and red-pepper flakes to marinate while the pasta…