Slice the sirloin into thin slices. Place in a large bowl.
2 pounds boneless pork sirloin roast*
Prepare the pineapple by peeling it, slicing it into quarters, and removing the core. Chop one of the quarters into a large dice and place it in the blender. Slice the other quarters into large wedges and set aside.
1 pineapple**
To the blender, add the onion, chicken broth, vinegar, ancho chili powder, garlic, chipotle chili, adobo sauce, salt, oregano, and cumin. Blend until smooth.
1 white onion, ½ cup low-sodium chicken broth, ¼ cup distilled white vinegar, 2 tablespoons ancho chili powder, 4 cloves garlic, 1 chipotle pepper in adobo sauce, 1½ teaspoons kosher salt, 1 teaspoon dried oregano, 1 teaspoon ground cumin
Pour the marinade over the meat and toss well to coat. Cover and refrigerate for 2 hours and up to 3 days.
Heat your grill, or grill pan, over medium-high heat. Grill the meat in batches until cooked through, 2-4 minutes per piece.
Grill the pineapple until charred.
Chop the meat and pineapple into small bite-sized pieces. Serve in tortillas with lime wedges, cilantro, and onion.
Lime wedges, Chopped fresh cilantro, Diced onion, 12 corn tortillas