Slice pork into thin slices. Place in a large mixing bowl or resealable plastic bag.
Add the roughly chopped onion into a blender along with 1 cup of the cubed pineapple. Add in orange juice, white vinegar, chipotle, chili powder, garlic, salt, and oregano. Puree until smooth.
Pour marinade over pork. Refrigerate and let marinate. Ideally, at least 4 hours or as long as possible.Heat a skillet or grill to high heat.
Heat a skillet or grill to high heat. Working in small batches, sear each slice of pork until cooked through, 2 to 4 minutes. Roughly chop the cooked pork.
Serve meat up hot on a warmed bed of rice add greens, freshly chopped cilantro, remaining pineapple chunks, sliced white onion, avocado and a lime wedge.
