Holding knife almost parallel to a cutting board, slice pork crosswise into very thin slices.
In a medium bowl, mix the pork, sherry, soy sauce, and ginger, set aside.
In a large bowl, whisk together the mayonnaise, vinegar, water, mustard, sugar, and pepper until well mixed. Add in the endive, radicchio, and arugula, mix to coat well.
In a large nonstick pan, spray nonstick cooking spray and heat over medium high meat. Add pork mixture from step 2, stirring quickly and continuously cook until pork is no longer pink, about 2 minutes. Add cooked pork to salad bowl.