Nothing can adequetly flush out toxins like intense IV fluids from your vet, but that shouldn't be necessary unless your dog starts to show signs of kidney failure.
Watch closely for increased urinating/drinking (it'll be a severe increase); lack of appetite, and signs of toxicity (lack of balance, confusion, etc).
In the meantime, make sure your dog has constant access to fresh water, as will keep his kidneys flushed as best as you can from home. I'm assuming you've already bought another dog food not on the recall list. And stay away from any table scraps, bones or other potentially salty treats for the dog, as water retention won't help.
Good luck, I hope your dog is just fine!