Green Beans with Toasted Walnuts and Dried-Cherry Vinaigrette

INGREDIENTS

• 1/2 teaspoon black pepper plus additional (for sprinkling)
• 3 tablespoons plus 2 teaspoons Sherry wine vinegar
• 2 tablespoons chopped fresh mint
• 1 1/2 teaspoons coarse kosher salt
• 1 1/2 pounds trimmed slender green beans (such as haricots verts)
• 1/2 cup walnuts, , chopped
• 1/3 cup dried tart cherries
• 1/3 cup minced shallots
• 1/3 cup extra-virgin olive oil
• 1 teaspoon sugar