Place the potatoes in a large pot and fill with water until the potatoes are covered by several inches. Salt water generously and bring to a boil. Continue to simmer until the potatoes are just fork tender, about 10 minutes. Drain the potatoes and set aside.
Meanwhile,while the potatoes are simmering, heat the olive oil in a large skillet over medium-high heat. Once hot, stir in the onion. Reduce the heat to medium and cook until the onions are soft and translucent. Add the dill and cook one minute more.
Remove the skillet from the heat, then add the green onions and vinegar. Add the potatoes, generously season with salt and pepper, and stir to combine, mashing potatoes slightly as you stir. This German Potato Salad is delightful served warm, room temperature or cold.