Combine 3 cups cooked brown rice with 4 tablespoons rice vinegar and 1/2 teaspoon kosher salt. Toast and crush 3 tablespoons pine nuts; set aside. Cover a sheet of tin foil with plastic wrap, and top with 1 sheet of nori (seaweed). Press 3/4 cup rice onto nori, leaving 1/4-inch borders at the top and bottom. Press ½ tablespoon crushed pine nuts into rice, and top with 1 thin slice prosciutto, 1/2 tablespoon blue cheese, and 2 tablespoons julienned pear. Roll foil tightly toward youl. Remove foil and plastic wrap. Cut roll into 1-inch pieces. Make 3 more; drizzle each with 1/4 tablespoon balsamic syrup.