KINGSTON — Mike Hein handed in his resignation as Ulster County executive at 10:17 a.m. Friday.The letter bearing Hein’s sweeping signature says the resignation takes effect at 11:59 p.m. Sunday. Hein has said he will become acting commissioner of the state’s Office of Temporary and Disability Assistance on Monday.The one-paragraph letter is addressed to Nina Postupack, the county clerk, and says:“In light of my appointment to serve as [...]