The type of slats I have quite a bit of experience with, on a Heliocourier H295, are merely mounted on rollers. At rest or taxiing they are extended by virtue of gravity and the geometry of the tracks and are retracted by merely being pushed back against the wing by oncoming airflow as the aircraft accelerates. At high angles of attack such as on short final, the relative wind shifts enough to cause them to extend (with four fairly loud bangs).
They must be modeled to close at taxi speed on the 262, eh?