Add chicken to a bowl along with the spices (cumin, coriander, paprika, cayenne pepper, cardamom, and kosher salt)
Toss chicken to coat well with spices
Marinate at least 30 minutes or overnight
Preheat oven to 375°F
Insert 4 wooden skewers into a thick piece of potato (or onion), trimming skewers if needed
Layer each piece of chicken on the skewers standing on the potato
Place in the oven on the bottom rack
Cook for 1.5 hours or until internal temperature reaches 165°F
Remove from oven and let stand for a few minutes
Slice the chicken shawarma meat
Assemble wraps with lavash bread, romaine lettuce, chicken shawarma, pickled onions, tomatoes, and garlic sauce
Wrap it up, slice in half and serve
