Using FlexPivotPage ToolStrip / Grid Menu
Grid Menu

The Grid menu appears similar to the image below and provides three options listed in the table below.

gridmenu

Total Rows Allows you to choose from Grand Totals, Subtotals, or None.
Total Columns Allows you to choose from Grand Totals, Subtotals, or None.
Show Zeros If checked, shows any cells containing zero in the grid.
Totals Before Data Adds a Total column or row before data.

Simply uncheck any of these items to hide the total rows, total columns, or any zeros in the grid.