Sorry, I learned from here, and it calls it "solving by colors" The faint green is because you can highlight only certain candidates, the deeper green is my highlighting.
http://www.angusj.com/sudoku/hints.php
Basically you "guess" and see if the candidate you pick is valid, and if it is, try the other one. It only works if there is a square made with 4 cells though, so not the best but it can work some times.
Thanks for the links, I'll take a look at them! My mobile app sometimes takes me 7- 10 minutes for a expert puzzle, and others I get stuck and end up going to 20 or more minutes...