Clitoral removal is the partial or total amputation of the clitoris. While it is most commonly performed against a woman's will in the context of FGM, there are adults in the West who choose it for themselves. This is usually in the context of a submissive relationship; in short, by removing their own sexual pleasure center, the slave becomes more able to focus on their master's pleasure.
Removal is usually done by surgical excision (be warned that the area is quite vascular), or more rarely by cautery (ie. burning it off). The area heals quickly and primary healing is usually not much more than a week.
The degree to which sexual pleasure is affected will vary greatly from person to person depending on their surrounding anatomy, how much was removed, how scarred the healing is, and just how they experience their bodies. A small percentage of women lose almost all sexual sensation, but most are still able to orgasm given appropriate stimulation. Some also experience other pleasure centers, such as their nipples, gaining in sensation level since the loss of their clitoris.
There are virtually no legitimate practitioners offering this procedure. As a result, Western clitoral removals are almost always done by the person's partner or a close associate.