Heat the sesame seeds and cumin in a dry frying pan for 1 minute, stirring constantly to stop them sticking, to release their flavours.
Transfer to a food processor and add the drained chickpeas, garlic, lemon juice and olive oil. Whiz to a coarse purée, adding a little more olive oil or water if needed.
To serve, spoon into a shallow bowl. Push the celery sticks and carrot batons into the dip.