Rinse, drain and pat the chickpeas dry. Add them to a foil lined baking sheet along with the oil, paprika, cayenne pepper and oregano. Season with salt and pepper and shake the tray to evenly coat everything. Pop in the oven for 20 minutes.
Prepare the tzatziki by combining the grated cucumber (squeezed of excess moisture), Greek yogurt, lime juice and chopped mint. Season generously with salt.
Dry toast the flat bread by heating in a griddle pan/ non-stick pan on a medium heat for around 1 minute. Use your tongs to gently fold the flatbread lengthways to form the shape of the gyros.
Assemble the gyros by adding a thick layer of tzatziki, a couple of lettuce leaves, remaining sliced cucumber, a handful of smoky chickpeas, tomatoes, onion and some crumbled feta.
Use any remaining tzatziki as a dip!