Heat the oil in a small frying pan and cook the onion for 4–5 minutes. Add the garlic and cook for 3–4 minutes. Add the spices and cook for a further minute, then remove from the heat and season with black pepper.
Cook the rice according to packet instructions, until tender.
Meanwhile, place half the chickpeas in the bowl of a food processor and pulse to chop. Add the lamb and pulse to combine. Scrape into a large bowl and add the feta. Stir in the cooked onions, then add the egg and mix until just combined.
Form the mixture into 16–20 balls, then thread on to 4 metal skewers and flatten each kofta gently. Place on a foil-lined grill rack and cook under a preheated grill for about 8 minutes, turning once, until cooked through and golden.
Meanwhile, fold the remaining chickpeas and chopped coriander into the drained rice and spoon on to 4 plates. Serve with the rice and a spoonful of tzatziki.