In a small bowl whisk together balsamic, EVOO, and spice blend. Pour into a resealable bag and add shrimp. Toss to coat and marinate for 30 minutes.
Soak 8 to 10 wooden skewers in water, 15 minutes. Heat a grill or grill pan to medium-high. Clean and lightly oil hot grill.
Thread shrimp, pineapple, and scallions onto skewers. Grill until shrimp begin to turn opaque, about 2 minutes, and then flip.
Continue to grill until shrimp are opaque throughout and pineapple and scallions are lightly charred, about 3 minutes.
Serve over cooked basmati rice.