She told them they were beautiful, touched their legs and took photographs of them against their wishes, while holding her own genitals, a court heard.
The fashion shop assistant, who came to Ireland as a holidaymaker, was sentenced to three months in prison.
Judge Anthony Halpin also registered Ching as a sex offender for seven years.
Ching, of Killery Terrace, Upper Dargle Road, Bray, had denied the charges.
Her defence argued there were "massive cultural differences" between the accused and the distressed victims, who ran from the cinema and gave evidence of feeling "violated and uncomfortable".
Ching was convicted of sexually assaulting two girls at IMC cinema, The Square, Tallaght on October 9.
The non-jury trial at Dublin District Court was shown pre-recorded DVD evidence from both girls, followed by cross-examination by video link.
The first victim told the court she had gone with her friend to see Taken 2 and instead went to a film they were not supposed to see -- The House At The End Of The Street.
She said the accused was already sitting in the cinema when they went in and she asked them to show her to her seat. "She said that she liked horror movies and started putting her hand up to her neck", the girl said.
Ching asked them their ages and if they wanted to take off their jackets because it was warm. She put her hand on the first girl's knee, but she pushed it away and Ching then "felt" her friend's leg.
Ching put both hands down her trousers and began touching herself and taking pictures, the girl said.
The second girl said the accused told them they "were beautiful and our mams should be proud". She asked to take their pictures and this made her "very uncomfortable", so she said no but Ching proceeded to anyway.
The second girl said Ching had been holding her own "private parts" outside her clothes with one hand while taking pictures.
"I felt violated in a way", she said. "I felt very upset and scared and very uncomfortable".