Place the potatoes in a medium saucepan with cold water to cover and add salt.
Cover and bring to a simmer over low heat.
Cook for about 15 minutes or until tender when pierced with a knife.
Drain and let them cool slightly.
Peel and cut into 1-inch pieces.
In a large bowl, gently fold together the cooked potatoes, slivered onion, orange slices, and pimiento.
In a small bowl, whisk together the red wine vinegar and olive oil.
Gently fold the dressing into the salad until evenly coated.
Season with salt and freshly ground black pepper.
Refrigerate the salad for at least 2 hours before serving.
Serve it cold for a refreshing touch.