Of course, that is possible.
Stepps to build an APK > 20 and < 100 MB (Play Store limit):
- remove some big files (png, jpg, mp3) from the assets (< 20 MB! /
better < 5 MB) - build APK
- decompile APK
- reinsert the missing files to the assets
- recompile your app
- sign APK
If you kown how it works, it takes about 1 min.