Cut the potatoes into wedges and add to cold salted water.
Bring to the boil and cook until tender (around 20 minutes).
Preheat the oven to 430F / 220c.
Once cooked, drain the potatoes and place on a baking sheet. Drizzle over the olive oil and add a few pinches of salt and pepper. Roast until golden brown, around 40 minutes.
Meanwhile, heat a some oil in a skillet on a medium high heat. Add in the sliced red onions and cook until softened, about 5 minutes. Set aside.
In the same skillet, add the green beans and cook for 5 minutes and set aside.
Mix together the ingredients for the dressing and keep refrigerated.
Once the potatoes are roasted, place them into a large bowl. Add in the cooked beans and onions and fresh dill. Pour in the dressing, toss to combine and serve immediately.