I've been using expss frequently and find it very useful, however, in some cases I have column values that are long strings which do not fit into the default column widths.
For example, the image below shows a column that needs widening. What htmlTables() options in expss can be used to widen columns?

There are several methods to increase width of the first column. Try one of the following:
Arguments
css.cellandpadding.rgroupare documented in the htmlTable package whichexpssuse for rendering HTML table representation (see ?htmlTable::htmlTable).