Can I hide RowShare columns?

To hide a column from your screen, click on that column menu, then "Hide this column". It will be hidden for you only, unless you save this as a table view. This has nothing to do with column permissions.

On the other hand, if you own the table, you can also decide that only table admins will see some columns. Click on that column menu, "Settings", then change the column permissions to "Hidden for other users".