To make the dressing: In a small bowl, whisk together the dressing ingredients until blended.

Preheat an oven to 400u00baF.

In a bowl, combine the potatoes, olive oil, salt and pepper and toss to coat. Transfer to a baking sheet or a small roasting pan and roast until the potatoes are tender, golden and crisp, about 45 minutes.

Cut the spears diagonally into 1-inch lengths. Place in a steamer rack over boiling water, cover the steamer and cook until tender-crisp, about 3 minutes. Remove the rack from the pan and rinse the asparagus under running cold water until cool.

In a large bowl, combine the potatoes, asparagus, arugula and dressing, to taste, and toss to mix. Divide the salad among individual plates. Serve immediately.