Heat Grill. FOR A CHARCOAL GRILL: Open bottom vent completely, and use a large chimney starter mounded with charcoal briquettes (7 quarts). Light briquettes. When the top coals are partially covered with ash (turning gray), pour your briquettes evenly over your grill. Set cooking grate in place, cover, and open lid vent completely. Heat grill until hot, about 5 minutes.
FOR A GAS GRILL: Turn all burners to high, cover, and heat grill until hot, about 15 minutes. Turn all burners to medium-high.
Clean cooking grate: Give it a good clean, then brush it with an oiled paper towel so your food does not stick to it.
Brush prepared pineapple with 1 tablespoon oil.
Place fish on one half of the grill.
Place pineapple and jalapeño on other half.
Cover and cook until fish, pineapple, and jalapeño have begun to brown, 3 to 5 minutes.
Flip fish, pineapple, and jalapeño over.
Cover and continue to cook until second sides of pineapple and jalapeño are browned and swordfish reads 140 degrees F with an instant read thermometer, 3 to 5 minutes.
Transfer fish to large plate and flake into pieces for the tacos. Cover with aluminum foil.
Transfer pineapple and jalapeño to cutting board. Finely chop. Then transfer to a bowl, and stir in chopped bell pepper, cilantro, and 4 tablespoons lime juice. Taste, and season with salt.
Warm tortillas on the grill by placing them directly on the grill for 30-45 seconds per side. Wrap tortillas in dish towel or foil to keep warm.