Scrape the avocado flesh into a small bowl and mash well. Add in all the other ingredients and mix until thoroughly combined.
If the dressing is thicker than you want just add more nondairy milk tablespoon at a time until it's just the way you like it. You can also add all the ingredients to a blender or food processor if you prefer a smoother dressing.
Recipe by Healthy Slow Cooking at http://healthyslowcooking.com/2014/06/12/no-added-oil-avocado-ranch-dressing/