In a food processor, or using a stick blender, blend the chickpeas, yoghurt, olive oil, harissa paste, tahini, lemon juice, salt & pepper and about 1/4 cup water until smooth. I like mine with a little texture - but others like theirs completely smooth. You decide.
Spread the hummus in a shallow bowl. Combine the extra virgin olive oil with the harissa and drizzle over, then sprinkle with the chillies, cilantro and zaatar.Serve with lots of flatbreads or crusty bread. Or serve alongside raw vegetables like carrot, celery, radishes etc.