Preheat oven to 400 degrees F.Wash a medium sized beet in cold water and dry thoroughly.Wrap in tin foil and bake in oven for 1 hour.Remove from oven and let cool before peeling skin with hands.Chop into bite-sized pieces.Combine all ingredients in a blender or food processor. Blend until smooth.Set aside until ready to dress salads.Combine arugula, beet, avocado, chickpeas and pistachios in a large bowl.Top with balsamic pesto dressing.