Outlaw teacher unions, then fire every single one of them. The best of them can be rehired sans the union and the outrageous contracts.
The bigger salaries are paid by suburban school districts not Chicago. Nor are the pensions from Chicago teachers particularly outrageous.
One of our major problems is the Double and Triple dippers in the pension funds. Work job 1- retire-collect pension, get job 2, work - retire - collect pension #2, repeat.