No salt or added oil
I find that pure tahini paste really needs salt, and if I were making a dressing I would also add evoo. That said, you can mix tahini with fresh lemon juice, salt, and a drop of honey--all to tase. Some finely chopped garlic would be a great addition, too.
Here is a recipe from Foods of the World TIME LIFE series:
3 medium sized garlic cloves, finely chopped
1 cup tahini paste
3/4 to 1 cup cold water
1/2 cup lemon juice
1 teaspoon salt
In a bowl, mash the garlic to a paste. Stir in the tahina. Beat in 1/2 cup of the water with a whisk. Add the lemon juice and salt and keep on whisking. Add up to 1/2 cup of more water, until the sauce has the consistency of thick mayonnaise. Taste for seasoning.
ottolenghi has a great yogurt tahini sauce recipe, which I absolutely love with roasted veggies. it’s a mix of greek yogurt, tahini, lemon juice and crushed garlic – for a dressing you can simply use a thinner yogurt or add a bit of water. i do prefer to salt it, but never felt it necessary to add oil.