Left: hand 扌, right: reject 屏 (That the buttocks 尸 combine 并 is to be rejected) [并= When you are coming out 丷 of the open temple's gate 开, you shall be combined/united. 并]
Mnemonic
When the hand is rejecting, it discards to get rid of it.
When you are coming out 丷 of a Buddhist temple 开 you shall be united. - [开 = image of a temple's entrance gate with double upper traverses, which actually means "open", as these gates have no door]
Tip: Go to the radicals that are contained in this character and learn all the characters with this radical systematically!
The app has many other functions, such as character selection according to difficulty, practice programs, handwriting recognition and success statistics!