Place the lamb, harissa and ground spices in a bowl and toss well to coat. Thread on to 4 pre-soaked wooden skewers or metal ones and set aside.
To make the chickpea salad, heat the oil in a large frying pan, add the onion and cook over a medium heat for 5 minutes until slightly golden and softened. Add the cumin seeds and chilli and cook for 1 minute. Add the chickpeas and cook for a further 2 minutes, then add the chopped coriander. Season well and set aside.
Cook the kebabs under a preheated hot grill for 8–10 minutes, turning once, until golden and cooked through. Return the chickpeas to the heat, add the measurement water and then toss with the rocket.
Spoon the chickpeas on to 2 warm serving plates and top with the lamb kebabs. Serve hot.