Preheat grill to medium-high heat and lightly oil grates. Marinate shrimp, if desired. Reserve some marinade to brush on kabobs for final stage of cooking. Skewer shrimp and pineapple on skewers in preparation for the grill. (If using wooden skewers, soak for 1 hour prior to prevent charring.)
Grill 2-3 minutes per side, or until shrimp are cooked through. Before removing from grill, turn to low and brush both sides of shrimp with the teriyaki sauce.
Serve over rice and sprinkle with optional sesame seeds, green onions and/or cilantro.