Top with the hard cheese and pour over the vinaigrette.
One of my tips for making vinaigrettes fast and easy is to pour the vinegar in a measuring cup first, then adding the olive oil, without pouring it out in between. You can even whisk it in the measuring cup if you want to save another dish to wash and don't intend to keep the extras!
Don't dress the salad until you are ready to serve it. If you dress the salad too early it can cause the arugula to become soggy.
You can also make this salad in a mason jar, simply pour in the ingredients and give it a good shake and it can be stored right in the fridge.