Make the dressing by whisking the mustard, cider vinegar and oil. Season to taste with salt and pepper.
Put the rocket in a large salad bowl. Finely slice the pear and add it to the rocket. Add the dressing to the salad and toss carefully to mix.
Layer most of the shavings of the pecorino through the rocket and pear salad, garnish with the remaining shavings and serve.