As busy as a one armed paper hanger. = very busy. Jack is as busy as a one armed paper hanger these days, he should slow down
two left feet = clumsy. What's the matter Hemi you got two left feet?
as helpful as a hole in the head = no use at all. Watch out! you're as much use as a hole in the head.
twist somebody's arm = get them to do something. All right you've twisted my arm, I'll help.
break a leg = good luck. Ok see you tomorrow, break a leg.
She/he has a green thumb!
word of mouthdirty wordsto have words witheat your wordsbuzz wordsspread the word
Not as slang or idioms, no. It just means to strike a ball, either with a bat, a stick, a racquet, or some part of your body.
an eye-opener
There are many idioms and phrases for 'on the back burner'. Some idioms and phrases for 'on the back burner' include 'pushing aside' and 'procrastinating'.
"Idioms for Being Afraid", "Idioms for Being Angry", "Idioms for Being Happy" are some examples of idioms found in the book "Found" by Margaret Peterson Haddix.
He did have many body parts in his refrigerator and a barrel of acid with some more body parts.
Arm and armpit are body parts. Additional body parts include anus and ankle.
Some websites that have idioms written in them include The Free Dictionary, Cambridge Dictionary, and Phrases.com. These sites provide definitions and examples of idioms to help users understand their meanings and usage in context.
Here is a link to some idioms. You can pick the "non-common" ones for yourself -- some people have heard certain idioms a lot and others have not heard the same ones, so you'll need to decide that part.
savvy, brainy
The best place is to go on your search engine and type in "list idioms" You can also look at this question for some examples.