Preheat the oven to 350 degrees F (175 degrees C).
In a large pot, combine the green beans, onion and water. Bring to a boil, and cook until tender, about 5 minutes. Drain, and transfer to a 2 quart casserole dish. While the beans cook, fry the Canadian bacon in a skillet over medium-high heat until crisp. Stir in with the beans along with the cream of celery soup and milk. Sprinkle bread crumbs over the top.
Bake for 30 minutes in the preheated oven, until heated through and sauce is bubbly. This recipe also works well to make ahead and refrigerate or freeze until needed. If baking cold, bake for 1 hour.