Thanks to my time spent working in Barcelona, I have a good stock of smoked paprika at home. It can be hard to find in the UK and is usually very overpriced. Smoked paprika, or 'pimentón ahumado', comes from the 'La Vera' region of Spain, and has Protected Designation of Origin status. Red paprika peppers are oak-smoked for 2 weeks as they dry and are then ground to a powder. Intensities vary from mild ('dulce') to very hot. Thanks to it's strong, smoky, flavour, and wonderful colour, pimentón ahumado is the spice used for chorizo.
As a vegetarian, I do not eat chorizo, but I use smoked paprika often in dishes, especially at this time of year- Bonfire season. It has become an essential ingredient for vegetarian chilli 'sin' carne for example. It can also be used to make spicy potato wedges, or in soups. The most popular brand is La Chinata: http://www.lachinata.com/ there are also some recipes on this page.