In a bowl, combine green olives, black olives, roasted red peppers, artichoke hearts, capers, olive oil, red wine vinegar, and oregano. Mix well.
Spread the olive mixture evenly on the bottom half of the bread.
Layer with shredded lettuce, tomato slices, and red onion slices.
Place the top half of the bread over the fillings.
Press down gently, slice into quarters, and serve.