When I run reports that are for board or other external audiences, I like them to look professional.  There is no way to adjust the margins for reports.  The left margin defaults to something around 1/4 inch.  My current solution is to print each report to Excel and then format.  Depending on how much data is going on the report, I would likely set the margin at 0.5 or 1.0 inches.  Sometimes I even like to center the report on the page.  My goal is to avoid having to print to Excel to further process.