Cook the quinoa in the vegetable stock for 10-15 minutes or until the germ separates. Cover with a lid and leave to absorb the rest of the stock.
Cook the broad beans briefly in boiling salted water for 3-5 minutes, depending on size, then drain and leave to cool. Pop the bright green beans out of the shells and place in a bowl. Chop the tomatoes and scoop into the bowl along with the olives, onion and feta.
Add the quinoa and stir. Whisk together the dressing ingredients then pour over the salad and toss before serving.