Mustard-y Quinoa, Potato, and Sausage Salad

Happy St. Patrick's Day! Although I don't have an Irish dish for you today, I do have a green one!  This hearty salad is absolutely delicious.  The potatoes, sausage, and quinoa all make this dish suitible for a main dish, and the arugula adds a peppery lightness.  The mustard-y dressing pulls everything together perfectly - yum!  As long as you store the arugula separately, the salad stores well in the fridge and is a great option to pack for lunch.

Mustard-y Quinoa, Potato, and Sausage Salad (adapted from Serious Eats)
Serves 2

1/2 cup quinoa
1 pound fingerling potatoes, scrubbed and cut into 1/2-inch pieces
Salt
1 large pork sausage, removed from casing and crumbled
2 T olive oil
1-1/2 T whole grain mustard
1-1/2 T minced fresh tarragon
2 cups arugula

1. Cook the quinoa in boiling water, according to the package instructions.
2. Place the potatoes in a pot, cover with cold water, and sprinkle with salt.  Bring to a boil, and then simmer until tender, about 5 minutes.  Drain.
3. Meanwhile, saute the sausage over medium-low heat in a non-stick skillet, until crisp.  Transfer the sausage to a paper towel-lined plate using a slotted spoon, and reserve the rendered fat in the pan.
4. Transfer the reserved fat from the sausage to a jar with a tight-fitting lid.  Add the oil, mustard, tarragon, and 1/8 tsp salt.  Screw on the lid, and shake well until combined.
5. Gently mix 1 T of the dressing into the potatoes while they are still warm.  When the potatoes are cool, mix with the sausage and arugula, and then toss with the remaining dressing.