Lurk the city till you find an isolated mook. Beat him, get the points which boost your health, and escape if more enemies start appearing. Repeat if necessary. --- http://i.imgur.com/qy3vx.jpg | Smidge ---
You regain health by getting points. The more awesome you perform, by doing long combos, the more points you'll get. --- I ran into a group of men trying to take an old lady's purse and decided it was my duty to help out. She was a tough old broad, but in the end we got her purse.