Cube SPAM in 1 cm chunks and brown. Boil chicken breast in 3 cups water until chicken is fully cooked. Cook celery and bell pepper in fat from SPAM. In a large pot, melt margarine and brown Rice-A-Roni, add cooked celery and bell pepper. Pour in stock from cooked chicken and both cans of soup and tomatoes (undrained). Add half of seasoning mix pack from Rice-A-Roni and stir. Add bay leaves, tabasco, cayenne pepper, and Cajun seasoning. Cook, covered, on low heat for 15 mins. Shred chicken, add chicken and SPAM and cook, covered, for 5 minutes. Add shrimp, uncover and cook 5 mins. on medium heat. Remove bay leaves and serve.