expression, kuru verb (irregular)
a perfect setup; a golden opportunity; a sucker begging to be taken
Idiomatic expression describing a situation where everything is conveniently arranged for one's benefit, often at someone else's expense. The literal image is a duck (good for eating) carrying a Welsh onion (a seasoning for duck) on its back, i.e., a ready-made duck dish walking right up to you. Used humorously or cynically.
See also: 鴨鍋
Him carrying a lot of cash is like a duck coming to you with a leek on its back—a perfect setup.
こんな好条件の仕事が転がり込むなんて、まさに鴨が葱を背負って来るだ。
A job offer this good falling into my lap—it's exactly like a duck bringing its own garnish.