Can you work for the same employer at the same time as a w-2 employee and a 1099 employee at the same time. Example selling insurance at an agency getting paid on w-2 for the clerical work and 1099 as for the commission on sales of the insurance from the same desk?

Sure you can do this. If there is a division of how you get paid such as clerical work and sales commission then it is perfectly legal. It just means that you have to pay the taxes on whatever you earn on commissions yourself through the 1099.

1099-Misc income is reported on schedule C. It is also subject to SE tax at 15.3% unless you are exempt.

How you will treat the 1099-Misc income, read: Your U.S. Tax Return: W2 or 1099: Employee or Independent Contractor.