Try adding "margin: 0;" to the table style (or to parent elements of the table)
In case you don't know already, itis easy to play quickly with HTML at a site like http://www.w3schools.com/html/tryit.asp?filename=tryhtml_basic
However, that won't reflect the 'outer' environment imposed by different browsers, eReaders etc.
The more explicit you make your HTML (eg explicit margin) rather than leaving it to environment support,
the more likely it is to appear the same (within reason of size etc) on all browsers/devices.
Probably worth making a fairly extensive style of your defaults that applies at the <doc> level.