Hold down the reset button on the back and then press the power button on the front. Either that, or do it the other way around (hold power and then press reset) or maybe it's the up button and reset. Anyway, whichever it is, this will wipe it totally clean.
To remove apps on my Handspring Visor, I hit the menu choice on the screen and the first option is "Delete", choose that and it has a list of apps. Just choose and delete. Alternatively, there's a shortcut to this (again, on my Visor) which is /D (bottom to top on the slash).