When I have a tuna sandwich, here's the routine:

1. Get light tuna in spring water
2. Put contents in bowl
3. Give can to dog to clean out
4. Put bread in toaster
6. Mix in mayo and seasoning salt to tuna
7. Throw away can that dog has licked clean
8. Take toasted bread and put slice of cheese
9. Apply tuna
10. Enjoy!!

Often I will make the tuna as described and just eat it with blue corn tortilla chips. The dog still gets to lick the can.