Yes apple cider vinegar is good for your kidneys and can help cleanse your kidneys.
You can mix some apple cider vinegar with some water and drink a few glasses of the apple cider vinegar everyday or whenever you feel like it.
The apple cider vinegar can also detox your body and prevent kidney stones and cleanse your liver as well so by drinking apple cider vinegar you can help prevent liver disease and prevent kidney disease.
Also if you have kidney stones the apple cider vinegar also helps reduce pain and inflammation when you have those kidney stones.
Apple Cider Vinegar is also mostly a dilute acetic acid and could contribute to acid build up in your body as well so if you have problems with acid buildup then you should watch how much apple cider vinegar you take.
But apple cider vinegar is perfectly fine for your kidneys and can improve your kidney health.