Hi,
You can kill the session and this way you will close any related cursors. But this is not safe.. You need to be sure about what to kill and when to kill.
The safe way is -> analyze your code and ensure your code is closing them correctly.
Analyzing the code and tuning your apps configuration will be the best way for achieving your goal.
Check this thread as well->
http://stackoverflow.com/a/12246631/1485955Also take a look at this one ->
https://docs.oracle.com/cd/E40329_01/admin.1112/e27149/cursor.htm