Place the steak in the freezer for 25 minutes (this will make the cutting process much easier). Using a sharp knife, cut the partially frozen meat against the grain into thin pieces.
For the beef marinade, add the olive oil, juice of 1 lemon, 3 cloves of garlic, spices, salt, pepper, and baking soda to a mixing bowl. Mix until fully combined.
Add the sliced meat to the bowl. Toss and coat the meat in the marinade with tongs. Cover the bowl with saran wrap and place it in the refrigerator for 30 minutes.
Add the thin-sliced onion and chopped parsley to a bowl, toss to combine, then set aside.
Add the yogurt, tahini, juice of 1 lemon, and 1 chopped garlic clove to a bowl and mix until fully combined.
Once the steak has marinated, heat a large skillet over high heat. Using a pair of tongs, add the meat slices to the hot skillet and spread them out evenly. For a nice golden-brown char, cook over high heat for 10-15 minutes. If your skillet is too small to fit all pieces, cook in batches.
Assemble the shawarma bowls by adding a cup of rice to the bottom of the bowl, followed by a generous amount of steak, a dollop of hummus, tahini yogurt sauce, onion parsley salad, and your other favorite toppings. Enjoy immediately.