Sautée the onion and garlic in a little oil until the onion is translucent
Add the walnuts and Sautée a little longer. Set aside to cool for a few minutes.
Add the Sautée and the remaining ingredients to a blender and blend until you have a thick, brown paste.
Add salt and blend. Repeat until you've salted to taste.
At this point you can do what you want with the paste. You can use it to coat chicken or fish before baking.
If you want a sauce or dressing, add water and blend until you have the right consistency.
You can substitute just about any nut for the walnuts -- hazelnut,almond, pecan, pistachio, or peanut