• Remove any bone from the pork shoulder and cut into large flat slices, about 1/4 to 1/2 inch thick.
• Poach the guajillos in boiling water until softenned. Then combine with the remaining marinade ingredients, and blend until smooth. Taste for salt and adjust to your preference. The marinade should taste earthy, salty, and a little sweet & sour.
• Combine the pork slices with the marinade. Make sure you mix it well through all the pork pieces, checking that all pieces are well coated. Cover in plastic wrap and marinade overnight.
• The next day, when ready to grill, heat oven or bbq to 350F. Using two bamboo or metal skewers, slide one disc of pinepple through, then slide the pieces of marinated pork onto the skewers, stacking them on top of eachother. End with another disc of pineapple. Grill for 1/2 - 2 hours.
• Separately grill the remaining pineapple discs until nicely charred. Chop and set aside for topping your tacos.
• Once the pork is cooked, slice the meat vertically. You may need to chop the pieces a little more to get them sized to your liking. Heat a skillet with a little oil and cook the chopped pork for a few minutes to add some char. If the pork wasn't 100% cooked through from the oven, this step will ensure everything is cooked through.

Making the tortillas (optional)

• Combine the masa harina with salt and water. Knead well, for a few minutes to re-hydrate the masa harina. The dough should be moist and pliable but not sticking to your fingers. Adjust by adding a little more water if it is too dry, or a little more masa if it is too wet.
• Let the dough rest in a zip loc bag for at least 30 minutes before using.
• When ready to use, roll out about 1.5 ounces (about the size of a golf ball) of the dough into a ball. Press flat between two pieces of plastic (like a zip loc bag into two pieces) in a tortilla press. If you don't have a tortilla press, use the bottom of a pie pan to press the ball flat. You can also roll it out with a rolling pin.
• On a hot skillet, cast iron pan, or a traditional Mexican comal, cook the tortillas about 45-60 seconds each side. Remove from the heat and keep warm in a tortilla warmer or wrapped in a dish towel. The steam will continue to cook the tortillas and make them soft.

Assemble the tacos and serve

• Assemble the taco with pork, pineapple, salsa, and cilantro & onions and enjoy!