One cup of olive oil to toast sourdough?

This deep-frying of bread slices (sometimes slightly stale) is one of the classic ways of preparing a canape.
It revives the bread and adds flavor, but no, doesn't use up all the oil specified in the recipe.
As Amelia says, it can be used to fry more bread, or strained and saved for future use.

We are pan frying very thick slices bread in a medium sized skillet that will absorb some oil . If you have leftover oil, you can always fry more bread and/or strain the oil and use it to fry something else.

That IS what the recipe says, so you are actually frying the bread. Personally, I would try heavily brushing both sides of the sourdough with olive oil and crisping up in a fry pan (like a grilled cheese sandwich). The bean and kale mixture looks wonderful!