Roast sesame seeds in a pan without fat. Take out and let it cool down. Pour chickpeas into a sieve, rinse cold and drain well. Wash the lemon hot, dry and finely grate the peel. Wash the cucumber, cut in half lengthwise and remove the seeds. Grate the cucumber coarsely. Peel garlic and chop finely.
Coarsely mash the chickpeas and sesame seeds with a hand blender. Stir in yoghurt, lemon peel, cucumber and garlic with a spoon. Season to taste with salt and pepper and serve.