eNotes has an impressive study guide that I have linked to below that provides in-depth review material of Kurt Vonnegut's short story, "Harrison Bergeron".
Your question specifically requests an example of a simile in this story.
Similes are a form of figurative language used by authors to compare two unlike things using like or as. A good way of remembering the meaning of simile is to think of the word "similar". Sometimes students confuse similes with metaphors. Remember a metaphor does not use like or as. It compares two things directly.
Simile Example 1: "Ordinarily, there was a certain symmetry, a military neatness to the handicaps issued to strong people, but Harrison looked like a walking junkyard."
Simile Example 2:"They leaped like deer on the moon."
A simile is a phrase which uses "like" or "as" to figuratively compare two similar ideas, things, people, images, etc. There are a great many smilies used in Kurt Vonnegut's short story, "Harrison Bergeron," which explores a world in which all people are rendered "equal" through the use of various intellectual and physical handicaps.
For example, George, the father of Harrison, is an extremely intelligent man who is forced to wear a transmitter that emits a sharp noise every twenty seconds, thus, preventing him from thinking too clearly. When the buzzer goes off, George's "thoughts fled in panic, like bandits from a burglar alarm."
When Harrison arrives at the studio where the ballet performance is being held, he is intent upon overthrowing the government. He tears "the straps of his handicap harness like wet tissue paper," and uses his thumbs to break his head harness "like celery."
The ballerina who agrees to dance with him and become his Empress "arose, swaying like a willow, and the two listen to the music seriously, "as though synchronizing their heartbeats with it."
Before Diana Moon Glampers shoots the pair down, they dance and leap "like deer on the moon."