On a cutting board, finely chop the garlic. Sprinkle with 1 to 2 tablespoons salt and press with the side of the knife, scraping it back and forth. This process makes a paste out of the garlic.
In a medium bowl, whisk the tahini with 2 tablespoons water. The tahini will thicken while whisking. Add another tablespoon of water and whisk until the tahini is smooth and glossy. Whisk in the garlic paste, zest, lemon juice, and yogurt. Whisk until combined. Cover and refrigerate until ready to use.
