Cook rice with water and salt in a pot over the stove top. In a large bowl, stir together cooked chicken, cooked rice, cream of chicken soup, mayonnaise, lemon juice, chopped celery, diced hard boiled eggs, water chestnuts (if desired) and slivered almonds. Spread into a greased 9" x 13" casserole dish. Stir crushed corn flakes and melted butter together and sprinkle over the casserole.