You are going to HAVE to gear them down if you use standard motors.
There is no way any of the motors on that page are strong enough to directly couple their shafts to the door. Besides, even if they were, the doors would fling open and slam closed. But by gearing them down from the 10,000+ RPM of your old school DC motor to maybe 1-100RPM, you'll easily achieve the torque you want. So I'd try looking for DC motors that already have gearboxes attached. Really, you want to go at this in the opposite direction you are. Look at what type of mechanism you are going to implement to translate the motor's work (rotation) to the operation of the door (swinging). From there, you can determine what kind of speed you need from the motor, and start shopping for it. The nice theing about DC motors is you can get one that's close to what you need, and alter the voltage to get it to exactly what you want.
It sounds like you just want a simple setup, not something that involves electronic controllers and such so stepper motors are out, although this is the application they were born for.
What do you plan to do to stop the motors when the doors fully open or close? Optical switches would probably be best, though microswitches are simplier to implement and will work, but you ought to be thinking about that.
The other bug I'll put in your ear is "Linear Actuator." Google around, and you'll see why I mentioned it.
