Hi, I don't know if there are any apps available. If I were you I would google common English idioms and try and learn some of the most common ones. There's lots of articles on this, I've found two for you which I've linked below.
Or if you're looking for slang, do you want to learn English slang in general or slang to a particular region?
<a href="https://www.lingopressbooks.com/english/interesting-english-idioms/">https://www.lingopressbooks.com/english/interesting-english-idioms/</a>
<a href="https://www.fluentu.com/blog/english/english-idioms-6/">https://www.fluentu.com/blog/english/english-idioms-6/</a>