The most difficult Chinese characters are not recognized by over 99.9% of Chinese people.
The most difficult Chinese character to write:嚻龘靐龖龘靐齉齾爩龗灪龖厵爨嘂嚻
The least common Chinese characters :亼亽亾仂仃仅仈仉仌仏仐仒仚仛仜仝
The simplest Chinese characters 1-10 :一 二 三 四 五 六 七 八 九 十
You can ask your Chinese friends and see if they know.