You slice something up by cutting flatpieces off if with a knife. When you are taking many slices off something, you try and make them all the same thickness.
Something is soaked if it is completely wet. Many foods require soaking before they can be cooked, or they will be hard in the middle even after they are cooked. Dried pulses like lentils and beans often need to be soaked overnight. The larger the bean the longer it will need soaking for.
Zest is the outside, coloured layer of citrus fruit like lemons and oranges. It is used to add flavour to many different kinds of food. Zest is removed from citrus fruit using a special tool called a zester, or just with a regular grater.
