In a food processor, combine orange juice, pineapple juice, garlic, onion, guajillo chiles, cumin, oregano, salt, and pepper.

Slice the pork shoulder thinly and place it in a mixing bowl.

Pour the marinade over the pork, ensuring each piece is well-coated, then refrigerate for at least 30 minutes.

Heat your grill or skillet over medium-high heat.

Add the marinated pork to the skillet or grill in a single layer. Cook for about 8-10 minutes on each side until nicely browned and cooked through.

Once cooked, remove the pork from the heat and let it rest for a few minutes.

Chop the pork into small pieces.

Warm the corn tortillas on a dry skillet for a minute on each side.

Place a portion of the chopped pork on each tortilla. Top with fresh cilantro, pineapple slices, and a squeeze of lime.