In a medium saucepan on medium-high heat, combine salt, potatoes and enough water to cover the potatoes. Cover and bring to a boil. Reduce heat to medium-low and simmer 10-15 minutes, or until desired tenderness.
While potatoes are cooking, prepare the dressing. In a small bowl, whisk together olive oil, vinegar, mustard, honey and chives. Season with salt and pepper, to taste. Set aside.
Drain the potatoes when they are done cooking and allow to cool before adding dressing. Place potatoes and radishes in serving bowl. Whisk dressing just before adding to the potatoes. Toss to coat and garnish with walnut pieces, if desired. Serve at room temperature or chilled.