I just began with electronics and I'm looking to build a 12v to 5v converter circuit. My plan is to use a Murata 78SR-5 to power either an Arduino or Rasberry Pi. I'm studying electronic design on my own as a hobby so I may not have adequate circuit design as of yet, but I have noticed that there are few available for purchase capacitors with leads|pins on them which can be used on solderless breadboards. I can't find a capacitor with the specific voltage range with leads already existing for use with solderless breadboard prototyping so I turn to SMD/SMT type.
What details are needed to know, if soldering leads/pins to SMD/SMT capacitors or resistors practiced? e.g. temp, wire size, wire alloy, etc.
When you say bread board, I'm assuming you mean solderless bread boards.
Soldering legs to individual SMD caps will be fairly difficult, and likely fragile. You should be able to buy through-hole caps that have sufficient voltage at RadioShack, or at just about any online electronics distributor (digikey, mouser, etc). Here is an example of a 50V through hole capacitor.
When I want to use SMD components on a breadboard, I usually attach them to a breakout board first, and then run wires or header pins from the breakout board. Bellin makes many different snap-out breakout boards like this. It's a little on the pricey side, though. You could make your own by cutting up some solder-type bread boards. SchmartBoard is another brand of adapters you could check out.