In a blender or food processor, combine the garlic, chili powder, paprika, chipotle peppers, pineapple juice, vinegar, pineapple cubes, salt, and pepper. Blend the mixture until smooth and set aside.
Preheat a large skillet to medium high heat and add the olive, chicken, salt, and pepper. Cook the chicken for about 5 minutes, then add in about 1/3 cup of the al pastor sauce. You will have some sauce left over.
Continue to cook the chicken in the sauce. Once the chicken is cooked through, remove the skillet from the heat. Divide the chicken among the tortilla shells and garnish with pineapple salsa. Enjoy!