Combine hoisin sauce, ketchup and jalapenos and set aside.
Season pork cubes with salt and pepper. Thread pork onto skewers. Grill over direct heat for about 4 minutes, turn and glaze with hoisin mixture. Continue cooking on grill until pork browns, about 8-10 minutes total cooking time.
Skewer pineapple and grill, glazing with hoisin mixture as well, for about 5 minutes.