Place the water, herbs, and garlic into a blender. Blend on high until the herbs are finely chopped, then pour the liquid into a bowl.
Stir in the tahini, lemon juice, and s+p until well combined. Add a little more water if the dressing is too thick or add a little more tahini if you think the dressing is too thin. Give it a taste and add more salt, pepper, or lemon as needed.