Slice tenderloins lengthwise almost in half, being careful not to cut all the way through. Press open to flatten. Place pork in non-reactive container. Combine teriyaki sauce, garlic and liquid smoke; pour over pork, turning pork once to coat well. Refrigerate, covered, 1 hour, turning pork over once during marination.
For each serving, to order: Over gas or charcoal grill, grill pork, turning once, 12 to 14 minutes or until meat registers 160°F on meat thermometer inserted into thickest part of meat. Let stand 5 minutes before slicing. Garnish with pineapple.