Simple answer, you can't
You can blow up your town and put everything in inventory
You can start another town
But you can not reset your current game to start over
creating a new account is one way to "reset" a game but know that if you use the same email for multiple accounts, servers can get confused and loose your games - all of them, not limited to TSTO.
it is better to start a new account with a new email
if you do not care about other games connected to your account, you could ask EA to remove your account and start a new one - I seldom remember this option because I have so many other games connected to Origin/EA