You can make this dressing sweeter by using apple or white grape juice instead of water. Or add a little spiciness by mixing in a tablespoon of spicy mustard. Or add creaminess by blending in a teaspoon of tahini or a tablespoon of raw cashews.
Combine all ingredients in a blender and process on high speed until liquified. Pour into a storage container and refrigerate until thickened slightly. Stir or shake well before using.
Notes
If you're not using a high-powered blender such as the VitaMix, you may get smoother results by soaking the raisins in the water until they are plump and then blending.