-Preheat oven to 325°F with rack in middle.
-Toast ¼ cup hazelnuts in a small baking pan 15 to 20 minutes.
-Cool to warm, than rub off any loose skins in a kitchen towel. Coarsely chop nuts.
-Cook 1 pound beans in a 6-quart pot of boiling salted water until just tender, 4 to 6 minutes.
-Run under very cold water and pat dry.
-In a large bowl, whisk together the following:
2 tsp grainy mustard
1½ tsp Balsamic vinegar
1/8 tsp sea salt
-Then whisk in:
4 tsp extra-virgin olive oil
1 tsp hazelnut oil
-Add the beans and the hazelnuts and toss well.
-Season with salt and pepper.