In a small bowl, mix together the olive salad ingredients and leave to marinate for half an hour.
Slice Italian focaccia in half and open both sides on a flat surface. Brush both inner sides with 1 tablespoon of extra virgin olive oil.
Begin layering mortadella, mozzarella, salami, provolone. Spread over the olive salad and replace the top. Press down to let the bread absorb the olive salad juices.
Wrap tightly in foil then weigh down for an hour. Cut into squares to serve. Secure each one with a cocktail stick.