You're going to have to put a silly piece of scotch tape over the left eye lens of your shooting glasses so that you're forced to use your right eye to get your front sight in focus. Don't use masking tape, cause that will simulate a closed eye and you don't want that. Keep both eyes open. You just want to make what your left eye sees blurry so that your right eye takes over the chore. You'll have to shoot this way for a few weeks if you shoot regularly to a few months if you just shoot once every couple weeks. It's a bit embarrassing, but all the experienced shooters will know why the tape is there.
Edit: After reading your post again, I thought I'd address a couple points. You don't want to shoot with your cross dominant eye. Take my word on this one. Others have tried, which is why the tape solution to training the non-dominant eye to become dominant is so popular. And yes many people start off with your cross-dominant eye issue. My wife was cross dominant and she successfully used the tape so that she was shooting comfortably with her right eye (both eyes open) in just a few weeks. She's a pretty dang good IPSC shooter now, often winning Ladies Production in matches but also beating most of the guys too.
Last edited by Gerry; September 26, 2011 at 10:21 PM.