Heat just a bit of oil on a skillet. Add thinly sliced banana. When the banana is just brown and getting soft, flip it over.
While this is going on, pop the vegan bread in the toaster if you want (I find it best just heated up, not toasted to crunchiness).
When the banana is done, spread some peanut butter onto the vegan bread, then add the banana slices. You might want to add some vegan margarine if you fear sticky peanut butter mouth.
Yum yum yum - my favorite sandwich ever!