Chop the garlic clove finely and then sprinkle it with salt. Using the flat edge of your knife, press the knife into the garlic and salt, scraping it along your cutting board. You want to achieve a garlic paste. Scoop the garlic paste up and place it into a small bowl.
Add the tahini to the garlic and whisk until combined. Whisk the mixture while you gradually add the lemon juice. The tahini will actually thicken at first, but by the time all of the lemon juice has been added it will become a nice creamy consistency. Add in the water, 1 tablespoon at a time until a nice creamy consistency has been reached. Add the cumin and more salt to taste and stir.
Drizzle the sauce over your side dish and sprinkle the sesame seeds on top.