On Android, when I click on "SIMULATIONS", select my saved simulation, click on "LOAD", the saved simulation directly starts running. When I click "BACK", I return to the editor and I expect that I will be able to edit my saved simulation, but my saved simulation is not opened in the editor. The editor contains the last simulation I created in the editor, and not the last simulation I loaded.

How can I edit a saved simulation with the Evolution editor ?

If you mean that you want to be able to edit the creature design after backing out of a simulation that you loaded from a file, that is currently not possible, but I already have it on my list of things to add with a future update.