Carrying things on a bike with one hand is common in the Netherlands. But there is a bit of a twist.
There is a Dutch saying, “met twee vingers in je neus.” The translation literally means with two fingers in your nose. This informal expression translates to do something very easily.
Such is the case of riding a bike while carrying something behind your back. Though it may not look that easy nor comfortable in some instances. But all you need is a back rack, one free hand and the will to do it.
But I think the English expression of with “one hand tied behind my back” is more appropriate. Though I would refrain from trying it “with your eyes closed.”