Summarize the following:
How many times you drain and rinse is up to you, but draining and rinsing it at least once is recommended.  Use a can opener to open the can, but don’t remove the lid yet. Holding the lid in place, flip the can over and hold it over the sink to drain the liquid. Pull off the top of the can, and be careful not to cut yourself. Take the tuna out of the can and place it in a strainer or colander. Rinse the tuna thoroughly with water, then press the water out using a clean hand or a paper towel. Place the rinsed tuna in a medium-sized bowl. Add the celery, onion, mayonnaise, lemon juice, and salt and pepper.  Mix the ingredients to combine. Be sure to thoroughly combine the ingredients so all of the elements are distributed evenly. Distribute the tuna mix evenly across 4 slices of bread and top each with another slice of bread to make 4 sandwiches.  You have the option of toasting the bread before spreading the tuna mix over it for a warmer, crunchier version. You can also substitute a roll or a croissant in place of the sandwich bread for taste and texture variation. Or you can avoid bread altogether and use the tuna mix over a salad for a lower-carb alternative.

Summary:
Drain and rinse the tuna. Combine the ingredients. Assemble the sandwiches.