What is a good lab surface to hot-air rework on?
Use a 12" x 12" ceramic floor tile. It will cost you less than one US dollar but if you want to splurge you can spend another dollar and buy some small stick on rubber feet for it. 



Any ESD mat isn't necessarily going to hold up against the heat. You need a high temperature version if you're going to be using a hot-air rework station.