Wash, clean and drain the arugula. Drain tomatoes on kitchen paper and cut into wide strips. Whisk eggs and milk with salt and pepper. Cut 1/3 rocket into coarse strips.
Heat the oil in a large coated pan. Briefly sauté the tomatoes and rocket strips in it. Pour eggs over them and let them simmer covered at low heat for about 10 minutes
Slide the omelette onto a plate. Top with mortadella and the rest of the rocket. Garnish with cherry tomatoes and olives if desired. Tastes good with farmhouse bread