Gently simmer the string beans until tender.
Heat a large frying pan with olive oil; add the onions, garlic and ginger and sauté until the garlic is fragrant and the onions are slightly golden.
Lift the string beans out of the water with a slotted spoon and carefully add them to the sautéed garlic, onions and ginger. Sauté the sting beans for another minute or two.
Mix the ingredients for the dressing and add to the string beans.