Preheat your oven to 400°F (200°C).
In a large bowl, combine chickpeas, olive oil, cumin, smoked paprika, turmeric, salt, and pepper. Mix thoroughly until all chickpeas are evenly coated.
Spread chickpeas on a baking sheet in a single layer. Bake for 25-30 minutes, or until chickpeas are golden brown and crispy.
While the chickpeas are roasting, prepare the tahini sauce. Combine tahini, lemon juice, minced garlic, water, and salt in a bowl. Whisk until the ingredients are thoroughly blended. If the sauce is too thick, add more water, a tablespoon at a time, until it reaches your preferred consistency.
Prepare the other toppings: slice the cucumber, thinly slice the red onion, chop the parsley, and cut the lemon into wedges.
Once the chickpeas are done, remove them from the oven and let them cool slightly.
Warm your pitas in the oven for 2-3 minutes, or until soft and pliable.
Assemble your vegan shawarma. Spread a generous amount of tahini sauce on each pita, then add a layer of roasted chickpeas. Top with cucumber slices, onion, and parsley. Squeeze a wedge of lemon over the top for a bit of zest.
Roll up the pita tightly, tucking in the ends as you go. Cut in half diagonally and serve immediately. Enjoy your delicious, healthy, and easy-to-prepare vegan shawarma!