At most you could use the sights on one of the guns, the other would be point shooting. More likely both point shooting. Accuracy would suffer (perhaps an understatement), but might be sufficient at short range. You would be most accurate firing both at a single target; firing at two targets simultaneously would be very difficult.
Tactically, there aren't a lot of reasons to do this. Generally, firing one gun well would be better than fire two guns less well. However, assuming you are in an area where missed shots are highly unlikely to hit a bystander, there could be some tactical applications. Suppressive fire, to allow you or someone else to advance, retreat, reload, get a door open or something. Using one gun in each hand, but only aiming and firing one at a time could provide an advantage, since you'd have twice the magazine capacity before you had to reload. However, you'd have to be really good at one handed shooting, and your off-hand would have to be nearly as good as your dominant hand. Reloading, needless to say, would be very difficult.
It's hard to imagine a circumstance in the real world where you'd have to do this, but in the world of action movies characters often get into situations where there's lots of bad guys (whom it's justifiable to just kill), and two guns might work well against closely packed bad guys in close quarters. Can also imagine an action movie hero walking up to two terrorists from behind and shooting them both simultaneously at point blank range by pressing both muzzles into their back. In the real world, it's hard to imagine a circumstance where any of that would be justifiable.
In the real world, you're responsible for every bullet you fire, so anything that makes misses more likely is to be avoided.