Wash potatoes and bring to boil in salted water, cook until tender. Drain, cool, peel and chop into cubes.

Remove bottom and top of green beans and also cook in salted water until done but retaining a bite. Drain, pour cold iced water to keep colour and set aside.

Meanwhile, either bake the onions over parchment paper at 200°C/400°F or boil in salted water until soft. Drain, discard outer leaves and cut into slivers.

Chop tomatoes into quarters.

Assemble all ingredients in a bowl and mix well with the olive oil and vinegar adding oregano sea salt to taste.

Allow to cool and refrigerate if not using straight away. Bring to room temperature before serving.