Pour the tahini paste into a bowl. Add the lemon juice, minced garlic, salt, sumac, and stir well.
Gradually add the ice-cold water, starting with half, and mix until smooth. Continue adding the rest of the water until you reach your desired thickness.
If the dressing is too thick, add a little more water. If it becomes too thin, add a little more tahini paste.
Sprinkle sumac on top. Enjoy!
