OK, you probably won't be able to go right to the edges of the page, because of the printer margins - the printer has to leave a blank bit round the edge to hold on to while it is printing.
But, if I insert a table, say 12 rows by 8 columns, and then take the mouse up to just outside the top left corner an icon appears of 4 arrows in a cross-hair. Click that to select the whole table, and then go to the centre of the table and right click to bring up the menu and then choose 'table properties'. You've got 2 tabs there called Row and Column, and in those you can set fixed sizes for the rows and columns. Mine will only let me swap between cm and percent, but 1/2" will be 1.27cm.
Is that any help?