These are best assembled and eaten right away, right after the bread comes out of the oven and is still warm.
Boquerones, or vinegar-cured anchovies, are incredible. They can be difficult to find in the U.S., and are much less salty than traditional anchovies. Sometimes, they are stored in a marinade that includes finely-sliced garlic cloves.
You can marinate your own boquerones at home by heating a few cloves of garlic in a small quantity of olive oil. Cool down the oil, and pour over the boquerones and allow them to sit for an hour or two. The garlic oil would also be great to use with a salad dressing.