Drain the chickpeas and pick over them to remove any loose casings. Put the chickpeas in a food processor along with the oil, tahini, lemon juice and garlic. Blend until smooth. Add some water, a tablespoon at a time, to thin to desired consistency (you will probably need 2 or 3).
To make rest of dish
Put the hummus in a serving dish, making a slight indent in the middle.
Dry toast the pine nuts in a small skillet/frying pan until lightly brown then set aside.
Finely dice the onion. Warm the oil in the skillet then add the onion and soften. Add a little more oil if needed to save it burning.
Add the lamb to the skillet along with the spices (cinnamon, allspice, cumin and cardamon). Cook over a medium-high heat until browned, breaking up a little and stirring regularly.
Put the lamb on top of the hummus, sprinkle over the pine nuts and parsley and a drizzle of EVOO then serve with pita bread.
Notes
You can easily substitute the homemade hummus for a tub of store bought. The topping is best enjoyed warm. Serving size assumes it will be shared with a few other mezze, but would serve less if with less other dishes, more if with a bigger range.