with one arm tied behind one's back
Also, with one hand; with one's eyes closed. Very easily, as in I can assemble that chair with one arm tied behind my back, or I could make a better dinner with one hand, or He can do that puzzle with his eyes closed. All these phrases are hyperbolic. Also see do blindfolded.
Words nearby with one arm tied behind one's back
with flying colors, pass with,
with good grace,
with half a heart,
with interest,
with it, be,
with one arm tied behind one's back,
with one voice,
with one's eyes open,
with one's pants down,
with open arms,
with reason