Hi,
You didnt mention your HANA DB is a primary or secondary connection.
J_3RMOBVED a custom report?
You can analyze the performance by using tools like SQLM, SWLT. For more information read the following.
You can also find many documents at ABAP for SAP HANA community.
There are many factors why your (custom) report performs bad. In general, post migration to SAP HANA DB, (custom) reports should improve performance.
I would suggest, study the reading from SQLM.
Thanks
Prakash K