The old "10 minutes per inch of thickness" guideline would apply, but that's just an estimate.
Check by cutting into it after about 5 minutes, and check again in a few minutes.
For this recipe, it's much better to have the salmon undercooked than overcooked. The interior should be less opaque than the exterior--think of a medium-rare steak.
I hope you like it! It's one of my favorites.