To make the Mayo-Barbecue spread, mix together mayonnaise and barbecue sauce in a small bowl. Set aside.
To make the Caramelized Pineapple-Onions, put butter and canola oil in a pan over medium low heat. Add the onions and cook until soft. Add the pineapple bits and stir the mixture every 5 minutes. Cook until onions are golden brown and are caramelized.
For the Bacon, lay bacon strips in a pan (do not overlap) then cook over medium heat. Soon the bacon will release its own fat. When bacon starts to curl and the bottom side starts to crisp up turn each slice to cook on the other side. Cook until desired crispiness is achieved. Transfer to a plate lined with paper towel to drain excess oil.
Preheat oven to 350 F (175 C). Line a baking sheet or dish with foil. Place the bottom half of the rolls on the foil then spread some mayo-barbecue mixture. Top with bacon slices, then the caramelized onions and pineapples, and lots of grated mozzarella cheese. Place the top half of each roll beside the bottom half. Brush each with melted butter then sprinkle with poppy seeds. Bake for 5 to 10 minutes or until cheese has melted.