I have students who run into the issue of having an opposing dominant eye vs a dominant hand.

One approach is to train you off hand to match you dominant eye, as you will have to do this anyway when it comes to the use of any weapon with a stock or scope. Or you would do the opposite of training your weak eye to match your dominant hand. These work, they just take more practice to make it feel natural.

The other option that works for pistols only is to simply adjust your grip slightly kicking the back end of the pistol over towards your dominant eye. Cross hand/eye shooting can be very fast and natural with very little practice in comparison to the above method, but you will still have to face the issue again when you move on to a stocked weapon.

The main thing here though is that you bring the sites to your eyes, not your head to your sights. This is very important for defensive shooting techniques as you progress through your training.

Hope this helps!