Arugula Salad with Pistachio Dressing

I had this salad at Provence on w. 19th a few weeks ago.   It was so amazing (better than my own dressing), so I had to ask for the recipe.

Ingredients:
Pistacchios
Grainy mustard
Parmesan cheese
Olive oil
Lemon
Arugula
Fennel (Optional)

Shrimp (Optional)

Instructions:
Grind the pistacchios into granules
Grind some Parmesan
Whip together pistacchios, grainy mustard, cheese, olive oil
and a bit of lemon juice.
Toss with arugula.
If you have some around, add a couple of slivers of fresh fennel and 4-5 cooked shrimp.