To earn this acheivement, you need to slice 8 fruits in one single slice.
This sounds tricky, and is partially luck based as you need 8 fruits to line up fairly nicely.
The easiest way to get this achievement, is to go into Arcade mode. Keep playing, and eventually you will hit a Frenzy powerup. When this happens, lots and lots of fruit will come from the top right and left of the screens.
Watch the fruit, and wait as long as you can. When you think you have eight in a row, make the slice. Hit all 8, and the achievement will pop.