sorry , but what ??
hoop stresses are the stresses that arise in a pressure vessel under pressure ... if you've modelled a pressure vessel, the FE output are the "hoop stresses".
but maybe you mean you want the stresses in the hoop direction ? 99% of times you get this by using a rectangular mesh, so the element direction align with the directions you want (pretty much i've always done it this way).
i think you can have FeMap transform the FE output into another co-ordinate system (ie create a co-ord system oriented to give you the stresses you want). if this isn't clear, ask the help desk, i've generally found them to be very helpful.