Ingredients

• 2 tablespoons white-wine vinegar
• 2 tablespoons plain low-fat yogurt
• 1 teaspoon Dijon mustard
• 1/3 cup walnuts, toasted and finely chopped
• Coarse salt and freshly ground pepper
• 2 tablespoons walnut oil
• 1 1/2 pounds fingerling potatoes, cut crosswise into 1/2-inch-thick rounds
• 6 ounces haricots verts or other green beans, trimmed
• 3 ounces baby arugula

Instructions

1. 1. Whisk together vinegar, yogurt, mustard, and the toasted nuts in a small bowl; season with salt and pepper. Add walnut oil in a slow, steady stream, whisking until emulsified.
2. 2. Bring a medium saucepan of salted water to a boil. Add potatoes, and cook until tender, about 10 minutes. Using a slotted spoon, transfer potatoes to a colander to drain. Return pan of water to a boil.
3. 3. Prepare an ice-water bath. Add green beans to boiling water and cook until tender and bright green, about 4 minutes. Using a slotted spoon, transfer to ice water to stop the cooking. Drain and cut into 2-inch pieces.
4. 4. Arrange arugula, potatoes, and green beans on a platter. Season with salt and pepper. Drizzle with dressing, toss to coat, and serve.