Jon,I found this on the net, haven't made it, but it looks as though it should work

Tahini (Sesame Seed Paste) Recipe

2 tablespoons sesame seeds
1/2 teaspoon sesame oil
1/4 teaspoon salt
1/4 cup tepid water

Blend sesame seeds in a blender and grind until smooth. Add sesame oil, salt, and then slowly add 1/4 cup of water while blending. Blend until completely smooth.

Yield: 1/2 cup

Note: Sesame seeds turn rancid quickly, so make certain yours are fresh. Be sure to store them away from light and heat and use quickly.