Put the chickpeas, tahini, lemon juice, half the garlic and the cumin into a food processor and process until smooth.
With the motor running, add the coriander and olive oil and process until smooth, transfer to a bowl and then cover and set aside.
Cook the capsicum and tomatoes on a lightly oiled chargrill pan or barbecue plate until the skins have blackened and then transfer to a plastic bag and allow to cool and then peel the capsicum and tomatoes (the best way to do this is to put a cross in the bottom and plunge into boiling water for about 30 seconds, remove and peel), remove the seeds and finely chop the flesh.
Chop the remaining garlic and combine with the chopped capsicum and tomatoes and season with sea salt and pepper.
Spoon the capsicum mixture onto the chickpea dip and serve with celery sticks for scooping.