It is common knowledge that practically we cannot add or create space in the kitchen other than what is already given to us. What we can do on the other hand, is to create an illusion of spaciousness. And we can do that by an intelligent choice of colours or by their very smart combination.
One very easy way to achieve this in a small kitchen would be to use white as much as possible, as white is known to be the best colour for small spaces. First of all the colour white reflects light and enhances the sense of space. When everything is white in a kitchen you feel like inhabiting a seamless space without limits or boundaries.