Preheat the grill to medium. In a large mixing bowl, combine the onion, mince and harissa paste.
Place the spinach in a colander and pour boiling water over it. Let it cool slightly then squeeze the excess water out. Add to the mince mixture along with the chick peas.
Shape into 12 small burgers and place on a shallow baking tray. Cook under the grill for 5 minutes on each side, until cooked through and no pink colour remains.
Meanwhile, place the cous cous in a bowl and pour over 250ml boiling water. Cover with clingfilm and set aside for 10 minutes. Stir half of the mint into the yogurt and season to taste.
Stir the remaining mint into the cous cous. Serve with the burgers, toasted pitta, lemon wedges and mint yogurt.