I'm not sure what these parts are called but I'm pretty sure they exist. Basically it's a timed relay that will hold the circuit closed for a certain amount of time. I'm thinking of rewiring the power window switch to go all the way down when you tap it like most newer cars do.

 

Using a timer will shorten the life of your window motors. Most installers instead use a module which senses the electrical noise from the motor and current flow. The DEI 530t is a favorite, it'll give you "one-touch" auto-up & auto-down on both windows.