What knife and cutting technique should I use for cubing bacon?
Cutting bacon into cubes was a regular prep task for me when I was cooking professionally, so I got very fast at it.  Here are the tricks I found:


Fully cooked (baked) bacon cuts MUCH faster and cleaner, and you can make perfect cubes
Don't use a serrated knife.  It'll be easier to cut with, but it will shred and fray the bacon as you slice, eventually making a mess.
Use the sharpest knife you have, especially for uncooked bacon.  There's already a tendency for it to slip and slide around, and a sharp knife cuts with less back-and-forth motion. 
You want a deep-bellied knife such as a santoku or Chinese cleaver, because you can slice through multiple stacks of bacon at once. 
Stack slices of bacon so you can cut multiple pieces at once. 
Try to work with 4" by 4" blocks of bacon, so the pieces aren't big enough to slip around as much.  With this size you're still able to do a lot at once, but it's fast
Organize your cutting board.  Pick one corner for whole chunks of bacon, then cut into strips and move to another spot, then finally into cubes which goes in another spot.


Now if I were a culinary school, you'd have paid a few hundred bucks to learn what I just told you.