So I don't really know what this means or what skiing has to do with an Farfisa organ, but I do love random graphics on electronic musical instruments. I am sure that the designer thought that this was somehow relevant.
The syntheslalom knob essentially is a pitch glide. When a key is pressed, the pitch starts lower than the key that you are pressing, then it glides up to the pitch. the knob is the offset of pitch or how far off the pitch is from the key you press, then the red lever is the time that it takes to catch up to the pitch. Nice effect. I wish that it there would be an option to start higher in pitch and fall down to the pitch of the key that is pressed. Many synthesizers have this feature and drum sounds (especially kick drum sounds) really benefit from a momentary fall in pitch at the begining of the sound.