Welcome to the board, Fliegender!!!
There is no way to "rest" in the game. You can change your spawn meter in the computer options screens so that you have fewer encounters during the night. Spending the time in dungeons or the like is another good way to pass an evening.
Also concentrate on learning some SUN spells and get Illuminate - Very helpful!!
Reset the gamma (on the computer options graphics screen) to increase the light as well.
After a while you should get used to adventuring at night and not think too much of it anymore - I rather like it myself!
Wyv