Preparation
1 Combine all of the tzatziki ingredients in a bowl and stir to combine. Season generously with salt and black pepper, then set aside for at least one hour for the flavours to combine (you can leave it overnight in the fridge if possible).
2 Pat the chickpeas dry with kitchen paper and place in the bowl of a food processor with the onions, garlic, parsley, coriander, cumin, harissa, lemon juice, flour and some salt and pepper.
3 Whizz until fairly smooth, then use clean hands to shape the mixture into around 16 small patties.
4 Heat the oil in a non-stick frying pan over a medium-high heat. Cook the falafels for 3-4 minutes per side until golden.
5 Serve in wraps with some tzatziki, chopped tomatoes and lettuce.