Once a cadet enters Starfleet Academy they will spend two years learning the general studies that every officer in Starfleet is familiar with, including the basics of each field (Engineering, Security, Science and Medical), which will get each of them up to an equal standard of learning. Towards the end of the second year a cadet will be asked to choose their field. All fields within Starfleet fall under one of the four major groups; Engineering, Science, Medical and Security. For the remaining two years in the Academy each cadet will receive advanced training in the discipline of their choice.

What you need to remember is that during those last two years a Cadet will focus on Security and Security only, so whilst it's permitted in the Academy to minor in an unrelated topic it would be almost impossible to find a Security Officer with a minor in Medical Nanotechnology. When you create your character you must think carefully about what you want them to know.

Contrary to popular belief, the standard Starfleet martial art is not in fact the Klingon art of Mok'Bara, which was something that Worf taught the officers and crew of the Enterprise. The Martial Art taught in the Academy draws upon a wide range of styles from Earth and other cultures brought together in the 24th century style of anbo-jytsu/anbo jyutsu, the ultimate way of the staff. More information on this can be found through Google.

The Security Officer, dependant upon their final field, will be required to learn advanced tactics and weaponry, small ship piloting, anti terrorist tactics, small combat unit combat practices, Starship weaponry and tactics, as well as military history and field practices which include semesters covering basic combat triage, weapon maintenance and repair and survival. This is by no means a definitive list, and no Security Officer will know all of these backwards, forwards and inside out. There will be a general smattering of knowledge, but some of these are more particular to Marines and Intelligence Officers.