You can use the "Map editing toolbar" to found a new city:
- press k to show the player list
- switch to the player "public service"
- click on the "Map editing tools" button in the main toolbar (switch to the "public service user" if the button is not visible)
- click on the "found a new city" button
- optional: click on the "grow city" button
A city costs 5.000.000 Cr !