Rinse the arugula and dry in a salad spinner or possibly a dish spinner. Rinse tomatoes and remove the stalk. Cut tomatoes and mozzarella into finger-thick slices. Arrange arugula, tomatoes and mozzarella on a platter. Season with salt and pepper. Drizzle olive oil over the top. Sprinkle basil leaves on top.
If you like, add a few drops of balsamic vinegar or a little lemon juice.