Set a steamer basket in a saucepan with 2 inches simmering water. Add 3/4 pound red new potatoes, scrubbed and halved(quartered if large). Cover and steam just until tender. 15 to 20 minutes. In a serving bowl, combine 1 1/2 teaspoons white-wine vinegar and 1 1/2 teaspoons Dijon mustard; season with coarse salt and freshly ground pepper. Add potatoes and toss; let cool, tossing occasionally. Add 1 tablespoon extra-virgin olive oil and 1/4 cup chopped fresh flat-leaf parsley to potatoes. Season with salt and pepper, toss and serve.