Brine and roast the pork (start 2 days in advance of serving):

1. In a container large enough to hold the pork loin, dissolve 1 cup of Kosher salt (no iodine) with 1 gallon of cold water.  Submerge the pork loin in the brine. Cover and refrigerate for 1 day but no more than 2 days.
2. When the pork is brined, heat the oven to 350℉. Remove the pork loin from the brine and dry completely with paper towels. Liberally season the pork all over with salt and pepper.
3. In a cast iron or other heavy pan over high heat, add 1 tbsp of olive oil. Add the pork loin and lightly brown all sides by rotating the roast in the pan. 
4. Place the pan with the roast in the oven. Using a meat thermometer inserted in the middle, roast until the pork reaches 135℉. Remove from the oven but leave in the pan. The pork will continue to cook and reach 145℉ before it starts to cool.
5. When the pork is cool enough to handle, wrap it in plastic wrap and place on a plate in the refrigerator.

Make the tuna sauce:

1. In a small food processor or blender, or using an immersion blender with a mason jar, add the anchovies, capers, mustard, pickles, garlic, tuna, eggs and lemon juice. Process until the mixture is well blended and the ingredients are well minced. Small chunks of the capers and pickles with be visible.
2. If needed, ask a friend to help with this next part. While the blender is running, very slowly drizzle olive oil into the mixture until you form mayonnaise. You want to make the mixture a little looser than store-bought mayo so it pours out of the jar but is not runny. You can use a little water or more lemon juice to thin it further.
3. Taste and season with salt and pepper. Refrigerate until ready for use.

Note: As shortcut, you can mix everything but the eggs and then mix with a good quality store bought mayo.

To serve:

1. To make it easier to slice, put the pork roast wrapped in plastic wrap in the freezer for 30 minutes. Remove, unwrap it and thinly slice the pork and arrange on a serving platter.
2. Remove the tuna sauce from the refrigerator and let it warm up for about 10 mins. Stir with a whisk to loosen. Spoon over the pork roughly as shown in the photos. Rough chop some additional pickles and sprinkle on the sauce.
3. Serve immediately or refrigerate the whole platter until ready to serve.