uninstalling an app will remove entry from /data/system/packages.xml, and delete package from
/data/app/ (apk file)
/data/data/ (user data and cache)
/data/dalvik-cache/arm/ (translated java bytecode to executable dalvik bytecode)

clear cache can performed from android settings
custom recovery twrp has option for wipe dalvik-cache

Uninstalling an app will remove entry from /data/system/packages.xml, and delete package from:

• /data/app/ (apk file)
• /data/data/ (user data and cache)
• /data/dalvik-cache/arm/ (translated java bytecode to executable dalvik bytecode)

Clear cache can performed from the android settings. Custom recovery twrp has option for wipe the dalvik cache.