Finely mince the garlic, gather them into a pile, and sprinkle a pinch of salt over them. Place the flat side of the knife's blade on top of the garlic and glide it back and forth, mashing it into a paste-like consistency.
In a bowl, warm the pineapple juice in the microwave, then dissolve the annatto powder.
Add the remaining marinade ingredients: mashed garlic, soy sauce, sugar, salt, and ground pepper. Mix well.
Place the sliced pork in a container or a resealable bag. Pour the mixture over the meat, coating each slice evenly.
Marinate in the refrigerator for at least overnight or up to 3 days. If you plan to cook it later, keep it in the freezer for longer storage.
To fry them, arrange them in a single layer in a skillet. Add about ¼ inch of water and partially cook them covered over medium-high heat for 5 minutes. Flip them halfway.
Remove the cover and allow the remaining water to evaporate. As the meat dries, the fat will start to render. If the meat is lean, you might need to add more oil to help it cook properly.
Constantly move the slices while caramelizing the outside for 3-5 minutes to prevent burning.
Cut them into bite-sized pieces. Serve and enjoy!