It is quite easy to fix the width of a column to a fixed percentage. If it only two columns, you only need to specify one.
Code:
.colw {
width: 75%;
}
and in HTML:
Code:
<table width=100%>
<tr>
<td class="colw">75%</td>
<td>the rest...</td>
</tr>
</table>
Keeping the table on one page is difficult. You could try something with page-break-avoid, but than it must fit on a page. With the different zoomlevels, that is hard to control.