Put one tin of chickpeas, 2 tablespoons oil, lemon juice, tahini, 1⁄4 cup water, salt and pepper in a small food processor, or use a hand-held blender, and process until combined and smooth.
Heat remaining oil in a large non-stick frying pan over high heat. Add the chickpeas, harisssa and sumac and cook for 2-3 minutes, or until lightly browned and warm.
Preheat a chargrill pan to high heat. Add a round piece of baking paper to the pan. Brush the avocado halves with oil and chargrill the cut side for 2 minutes or until lightly charred.
To serve, spoon the hummous into the centre of each avocado. Top with harissa chickpeas, pomegranate, snow pea shoots and sprinkle with extra sumac.