with one hand behind your back

with one hand tied behind (one's) back

Easily or effortlessly; encountering no difficulty or resistance (while doing something). I'm a professional musician, so that song is hardly a challenge—I could play it with one hand tied behind my back! Are you kidding? Montgomery is a powerhouse boxer. He'd knock that kid out with both hands tied behind his back!
See also: back, behind, hand, one, tie
Farlex Dictionary of Idioms.

with one hand (tied) behind your back

1 with serious limitations or restrictions. 2 used to indicate that you could do something without any difficulty.
See also: back, behind, hand, one
Farlex Partner Idioms Dictionary
See also:
  • do something with one hand behind your back
  • with one hand tied behind (one's) back
  • with one hand tied behind back
  • with one hand tied behind your back
  • could (do something) with one arm tied behind (one's) back
  • with one arm tied behind (one's) back
  • with one arm tied behind one's back
  • with both hands tied behind (one's) back
  • with an arm tied behind (one's) back
  • cakewalk
References in periodicals archive
Caption: Stand or sit with one hand behind your back. Place your other hand on your head and gently pull your chin towards your armpit.
Stretch Away That Pain in the Neck: Neck pain and stiffness is a problem for many seniors, but simple stretching exercises can ease the discomfort
If you're an AE or AT, do you remember being told in "A" school that you should work with one hand behind your back while working on energized circuits?
Don't get grounded