Drain the chickpeas. Cut the tomatoes into thin wedges, cut the spring onions into rings and roughly chop the parsley. Mix all the salad ingredients together in a large bowl.
For the dressing, crush the clove of garlic and stir in the yogurt and lemon juice until smooth. Season the dressing with cardamom, cumin, salt, pepper and sweetener to taste.
Pour the dressing over the salad, let it steep for a moment and serve.