1.
Using a powerful blender, blend the onion, garlic cloves, vinegar,
apple cider vinegar, orange juice, salt,
olive oil and black pepper until it forms a smooth sauce (if it is very thick, you can add a splash of water).
2.
Cover the prawns with the sauce and stir to coat (ideally, leave the prawns in the refrigerator for a few hours to marinate).
3.
Cook the prawns (without the sauce) in a frying pan with a bit of
extra virgin olive oil. Then remove them from the pan and set aside.
4.
In the same pan, brown the pineapple sliced into pieces.
5.
Heat the corn tortillas and fill them with the prawns and pineapple. Finally add the cilantro, lemon juice and some of the sauce, to taste.