Slice the ciabatta bread in half.
Thinly slice lettuce, tomato, cucumber, and onion.
Prepare ham or chicken slices as desired.
Heat olive oil in a pan and lightly toast the inner sides of the bread.
Place the prepared vegetables, ham, and sliced cheese on the bread.
Drizzle with mayonnaise or mustard sauce.
Cover with the other half of the bread to finish the sandwich.