Heat Vegetable Oil In A Large Skillet Over Medium-High Heat. Stir In The Sirloin Strips, And Cook A Few Minutes Until The Strips Begin To Brown, But Are Still A Little Pink. Stir In The Onion And Garlic; Cook For 2 Minutes. Add The Celery And Ginger, Continue Cooking Until The Onion Has Softened, About 3 Minutes. Season With Soy Sauce And Chili Oil. Divide Among Hoagie Rolls And Serve.