In a bowl, whisk together the tahini, 3 teaspoons za'atar, and garlic.
Add the lemon, water, and salt, and whisk again until smooth. Taste and add more za'atar, salt, or lemon as desired. The dressing will thicken as it sits, especially after refrigeration.
Serve now as a dressing, sauce, or dip, or transfer to a lidded jar or container and refrigerate until ready to use. Whisk in a splash of water or lemon juice if the consistency is too thick.
