To make the marinade, whisk the olive oil, vinegar, lemon juice, shawarma seasoning and garlic until well combined in a large bowl.
Add steak strips to the bowl, sliced onions, and bay leaves, and toss to fully coat the beef with the marinade. Let it sit in the fridge for 1-2 hours
When ready to cook, transfer to a bottom-heavy saucepan and cook until beef is cooked though, about 8-10 minutes
To make the tahini sauce, place all the ingredients except for the water, together in a food processor or bowl and blend until well combine. Slowly add the water to reach desired consistency.
Assemble the beef shawarma with pita, tahini sauce and vegetables of choice.
