Cut corned beef slices crosswise into thin strips; set aside.
Place potatoes in a large saucepan. Cover with water; bring to a boil. Cook 5 minutes. Add leek; cook an additional 2 minutes. Drain well. Combine potato mixture and slaw in a bowl; toss well. Set aside.
Heat oil in a large nonstick skillet over medium heat. Add corned beef; sauté 2 minutes. Add vinegar and next 5 ingredients (vinegar through pepper); cook 1 minute, stirring frequently. Pour vinaigrette over potato mixture; toss until well-blended and wilted. Serve immediately.