Make the Mayo: Blend all mayo ingredients in a blender or food processor until smooth. Adjust seasoning to taste.
Prepare the Salad: Slightly mash the chickpeas in a large bowl—just enough to break some up.
Mix It Up: Add grapes, celery, apple and walnuts. Pour the tofu mayo over and stir to combine.
Chill and Serve: Refrigerate for at least 30 minutes before serving to let the flavors meld.