Add the tahini, lemon juice, fresh sage leaves, and minced garlic to a blender. Blend on high until the mixture is completely smooth.
Pour in the olive oil, maple syrup, and salt, then blend again to combine. With the blender still running, slowly add cold water, 1 tablespoon at a time, until the dressing reaches a thick but pourable consistency. Taste and adjust seasonings as needed. If the dressing is too thick, continue adding water until it's perfect for drizzling.