Strain the brine from two cans of young jackfruit. Thinly slice each triangle lengthways and pop them in a large bowl.
Add the chickpeas and the remaining shawarma "meat" ingredients and stir to combine. Cover with a clean cloth or cling film and refrigerate for at least 2 hours or overnight.
Preheat oven to 190 degrees C (375 degrees F).
While the oven is heating, remove the marinated jackfruit from the fridge and spread it out over a roasting pan or tray.
Place the tray in the oven and roast for 35-40 minutes or until some of the jackfruit edges are slightly charred. Remove from the oven when roasted.
While the jackfruit is roasting, add the lemon tahini sauce ingredients to a blender and blend until smooth. Add more water if needed to thin out. Transfer to a jar.
To serve the vegan shawarma, warm a pita gently on a dry pan over medium heat for a minute or two, turning halfway through. Remove from the heat and lay the pita on a plate or board and smear with a good dollop of hummus. Add the sliced lettuce and tomato followed by a good handful of the roast jackfruit and chickpea mixture. Add pickles - if you're adding them - and drizzle with a little lemon tahini sauce.
Fold the bottom of the pita up and then roll from the side to make a wrap. Grab and napkin and dig in!