Does English have a version of "pouring water on a goose"?

Solution 1:

Exactly as @Yosef Baskin has said in a comment, this translates perfectly from goose to duck in the phrase like water off a duck's back.

(like) water off a duck's back
informal : having no effect on someone
He tried to convince her to take the job, but his advice was like water off a duck's back. Merriam Webster

This tangible metaphor and/or simile shows how one can be unaffected or impervious to an event, like the idea behind outcome independence. The ducks, like the geese, do not let the water stick; they take it as it comes and keep on going.

Pouring water on a duck to as useless as a chocolate teapot or to keep with the aquatic theme, a fish with a bicycle; it's pointless.

Dunn's modesty is appropriate, as 'A needs a B like a C needs a D' was a well-established format in the USA many years before 1970; for example, this usage in the Connecticut newspaper The Hartford Courant, December, 1898:

The place [Aragon, Spain] didn't need an American consul any more than a cow needs a bicycle; for it had no trade with America, and no American tourist ever dreamed of stopping there.

Or this, from The Detroit Free Press, October, 1906:

The house didn't need a fire then any more than a horse needs a shave.