Place the tahini, yogurt, lemon juice, garlic, ½ teaspoon salt, and ½ cup of water in a blender. Blend until smooth and thick. It should be the consistency of lightly whipped cream. Add a little more water if necessary. Taste and add more salt if needed. Transfer to a small serving bowl.
Notes
To make dairy-free, either substitute with dairy-free Greek yogurt or simply omit and add an additional ½ cup tahini.