Preheat oven at 375 degrees F.
In a blender combine chiles, garlic cloves, vinegar, juice and a pinch of salt and pepper. Blend until all ingredients are combined, consistency should be paste like. Set aside.
Place a slice of meat between two sheets of plastic wrap. Using meat mallet (or rolling pin), gently flatten meat until it is very thin. Continue to do this for remaining meat.
Grab a baking pan and spread with oil. This will help your meat to not stick to baking pan. Start by putting a couple of slices of meat on pan. Season with salt and pepper. Spread adobo paste on meat until fully covered, add about 3 slices of bacon, top with slices of pineapple and repeat. Repeat this process until you create a stack of meat.
Let meat marinade for 2 hours in the refrigerator. When meat is done marinating drizzle oil on top and cook for about 35-50 minutes.
When the adobada is ready transfer to a cutting board and thinly slice the stack of meat.Do not discard of the oil left on the baking pan. The leftover oil will be used to heat the tortillas. Once your meat is sliced, grab a tortilla and smear leftover oil from pan on both sides. Warm tortillas at medium heat on a pan. Serve tacos with onion, cilantro, lime, and your choice of fresh salsa.