Heat 2 tbs oil in a non-stick frying pan over medium-high. Add the onion and cumin and cook, stirring often, for 5 minutes until soft. Increase heat to high, add the mushrooms and cook, stirring occasionally 5 minutes or until mushrooms are tender. Set aside to cool to 10 minutes.
Meanwhile, place the chickpeas, 2 tbs yoghurt, tahini, 1 tbs lemon juice and remaining 1 tbs oil in a food processor. Process until smooth. Transfer to a bowl.
Drain excess moisture from the mushrooms and add to the chickpea mixture with the chives and remaining yoghurt. Season with salt and pepper and stir gently to combine.
Place a piece of wrap onto the surface, cover and refrigerate overnight if time permits. Sprinkle with extra chives & drizzle with olive oil to serve.
