If you have control of the width of the table, insert a padding-left on all table cells and insert a negative margin-left on the whole table.
table {
margin-left: -20px;
width: 720px;
}
table td {
padding-left: 20px;
}
Note, the width of the table needs to include the padding/margin width. Using the above as an example, the visual width of the table will be 700px.
This is not the best solution if you're using borders on your table cells.