Place all ingredients into a small bowl and whisk together.
Taste for flavours and adjust as desired. Add a teaspoonful of water at a time to thin out the sauce and make it more pourable.
Store leftover sauce in an airtight container in the fridge. The tahini sauce will thicken in the fridge. Add a teaspoonful of water to thin out the sauce after it has been in the fridge.
Notes
Depending on how much lemon you use, how thick your tahini paste is, and what you are using your sauce for (condiment dip or drizzle), you may need to add a teaspoonful or more of water to thin out.
Find tahini paste in the International aisle, 'natural' aisle or peanut butter aisle in most grocery stores. Stir well to incorporate oil before using. Store in fridge after opening.
STORAGE - the sauce stores well in the fridge in an airtight container all week. It will thicken in the fridge.