Bring pork shoulder to room temperature and pat dry.  Slice the pork shoulder into ¼” slices, which is roughly the width of your pinky finger.  Move to a large bowl that will fit into your refrigerator. 

In a bowl, whisk together the achiote paste, chili powder, garlic powder, oregano, cumin, salt, pepper, vinegar, and pineapple juice. 

Whisk vigorously until the marinade is smooth and well combined. 

Pour the marinade over the pork, then stir to make sure they are coated on all sides. Use a gloved hand to make sure you’ve worked the marinade into all of the meat.  Cover the bowl and refrigerate for a minimum of two (2) hours. 

Light your charcoal or pellet grill and prepare it for cooking at 350oF.  Pre-heat your oven or gas grill to 350oF.

Remove the pork from the refrigerator and let come to room temperature.

Put your al pastor skewer stand on a baking sheet or plate.  Put a slice of the pineapple and half a white onion on the skewer.  Layer the sliders of pork on the skewer over the onion and pineapple alternating in the shape of an “X” through the skewer, until you have nearly reached the top of the skewer or you have run out of pork.  Top with another ring of sliced pineapple.

Smoke for about 1½ hours, until the pork is slightly charred on the outside and has reached an internal temperature of 160oF. Rest the meat for about 10 minutes, then carve off thin slices of pork. 

For more crispy pork, increase the heat on your grill or over to 425oF and slice off the crispy exterior and then cook an additional 5-10 minutes to char again.  Repeat the step as desired. 

Build your taco with chopped al pastor, minced white onion, and diced cilantro. Serve with lime wedges.