Combine a quarter of the lemon juice, ½ cup olive oil, salt, black pepper, paprika, red pepper flake, and cinnamon in a gallon plastic bag with chicken breasts. Marinade in fridge for 2 hours, or overnight.
Preheat oven to 425 degrees.
Pour chicken and marinade into a lined 9 x 13 baking dish. Top with onions. Roast 40 minutes. Slice chicken thinly.
Make tzatziki sauce by blending remaining lemon juice, ½ cup olive oil, greek yogurt, garlic, onion powder, and dill.
Spread hummus on pita and layer on chicken, onions, and sliced carrots. Top with tzatziki sauce and additional dill.
Recipe by Rachel Schultz at https://rachelschultz.com/2019/01/21/chicken-shawarma-in-the-oven/