create user - limited priviledge

i want to create unix user account (usera) for outsider so that they can run program that exist in /application/xxx/.

The account have their own home directory (/home/usera).

But on the same time the user cannot run any application/command either than in /application/xxx/.

User can only browse their own home directory and avoid from accessing others.

for your information :
usera need to access Common Desktop Environment(CDE) for information.

Please don't cross post. I've already posted some suggestions here