I want to create one or more static pages that retain the header, merge the left and center column (only one broad column that I can enter static text, images, etc.) and retain the right column but with only one widget not the usual three as in my regular blog pages. How can I customize such a page? Are there any tutorials on such customization within the Atahualpa theme? Thanks.

You could create a page and exclude the sidebars (ato->Style & configure SIDEBARS) and use the 'widget logic' plugin to control the widgets showing up