Prep ingredients per the instructions above.
Mix the ingredients for the cucumber water.
Mix the oil, vinegar, olives, garlic, shallots, and oregano in a bowl until fully combined.
Drizzle the inside of the ciabatta with oil-olive mixture on both halves, and layer with mortadella, ham, mozzarella, salami, and olive mixture.
To serve: Cut muffuletta in half and enjoy with chips, pickle, and cucumber water.