we have two aspects here :- 

1.column store 

2.Row store

to find column store utilization :-SELECT round (sum(MEMORY_SIZE_IN_TOTAL)/1024/1024) AS "Column Tables MB"  FROM M_CS_TABLES;

to find row  store utilization :

SELECT round (sum(USED_FIXED_PART_SIZE + USED_VARIABLE_PART_SIZE)/1024/1024) AS "Row Tables MB" FROM M_RS_TABLES;

If you want to migrate a particular table from one node of HANA to another for performance or space issue :- 

1. To view current location  of table - 

open SQL editor on HANA studio and run the sql query :- 

select * from "SYS"."M_TABLE_LOCATIONS" order by LOCATION, table_name

2. To view current location  decide the node where you want to move it and run the below  query on SQL editor of HANA studio:- 

ALTER TABLE MOVE TO ‘node:port number’