Wash the ginger and turmeric and gently scrub them with a vegetable brush.
Grate the ginger and turmeric and zest the lemon. Cut the lemon in 4 and retrieve the pulp from one of the quarters.
Blend. Add the tahini, water, grated turmeric, grated ginger, lemon juice, lemon zest, lemon pulp, maple syrup, and salt to a small blender jar. Blend until smooth. Alternatively, mince the lemon pulp with a knife and combine everything in a small bowl.
Transfer to an airtight container and store in the refrigerator for up to a week.
Notes
Be careful when cooking with turmeric, especially fresh turmeric root, as its stains are difficult to get out of clothes and countertops.
Use a glass jar for blending if possible. Blending fresh turmeric in a plastic jar will most likely turn it slightly yellow.
If your blender jar is stained, let it rest in the sun for a day and the yellow color should completely fade away.
Add more water if you like your dressing on the runnier side.
The color of the dressing will intensify after a few hours and turn from light yellow to bright yellow.