Preheat a griddle pan or heavy skillet over high heat until very hot.
Slice the pineapple lengthways into thick slices and cut away and discard the core.
Grill the pineapple slices on both sides until golden brown and charred in spots, about 2–4 minutes per side; transfer to a board to cool.
Once cool, chop the grilled pineapple into small dice and place in a mixing bowl.
Add the finely diced red peppers and red onion, chopped cilantro, lime juice, and very finely chopped pickled jalapeño (if using) to the bowl; stir to combine.
Season the mixture with salt to taste and mix well.
Spoon the pineapple salsa into lettuce leaves to assemble tacos and serve with extra lime wedges to spritz as desired.