Chef Anthony Bourdain doesn't take kindly to "young punks" who piss in restaurant kitchens ... so he went to Twitter and UNLOADED on Justin Bieber.

After TMZ posted the footage of JB relieving himself in a janitor's bucket in an NYC restaurant kitchen, Bourdain tweeted -- "The chef should have put his foot up this young punk’s ass."

The CNN star continued, "My dishwasher ain’t cleaning that up, squirrel balls!"

There's more ... "Looking forward to seeing him open for Menudo at the State Fair— in about ten years."

And just for good measure: "In a preemptive strike, I plan to tell my daughter that Justin Beiber tortures puppies."