For the pasta salad with arugula, tomatoes and pesto, cook the pasta in water until al dente.
Halve the tomatoes and coarsely chop the mozzarella. Strain the pasta and rinse with cold water.
Mix the mozzarella, tomatoes, arugula, salt, vinegar and pesto together well and fold in the pasta.
Arrange the pasta salad with arugula, tomatoes and pesto and serve.