Um, can't wait to pick on people 😝😝. No, I don't of course. I remembered that my alliance leader once told us to practice spying on dead castles not on active players because our alliance try to avoid aggression at all costs. 
If you choose non aggression policy, make sure that you are spying on players with 0 Army Might in his profile, then click the icon at bottom right.
The aim of this practice is to level up your assassin. I have performed a few missions yesterday so Shue Uemura here is already level 2. Just click Start. Mission takes 15 minutes. When I did this yesterday. I have some extra play time and Adventures were just common ones consuming 10 energy in 2 minutes.
This is how it looks like when you are up to no good at someone's city 😈
Example of reports. If your spy succeeds, you will get 20 energy and extra resources in just 30 minutes.
Example: before espionage on the left and after on the right. Extra energy, extra resource reward. Enticing, isn't it? Go on now, spy on people.