One of our favorite restaurants here in southern New England is The Back Eddy in Westport, Massachusetts.Great water views, great food, wonderful people.
One of their best-selling appetizers is deviled eggs, topped with raw tuna or without. My version has none of the finesse of their original dish, but it has a lot more tuna and all the flavor…which works for me!

6 hard-boiled eggs
1/4 cup + extra mayonnaise
8 oz. high quality raw tuna
3 tablespoons soy sauce
1/2 teaspoon chili oil
1/4 cup finely chopped scallions
1 teaspoon sesame seeds
handful fresh spinach, or cucumbers (see below)
My newest favorite method of hard-boiling eggs (thank you, Alton Brown!) is to put them in a pot of boiling water, with a steamer basket inside. Place the eggs inside when it’s boiling, put the lid on, and steam for 12 minutes. Then plunge the eggs into an ice water bath for 3 minutes. Perfect every time, and they peel easily.
The official word on making sure there are no parasites in raw fish requires freezing and storing fish at a surrounding temperature of -4 degrees Fahrenheit or colder for seven days; or freezing at a surrounding temperature of -31 degrees or colder until the fish is solid and storing at the same temperature for 15 hours; or freezing at a surrounding temperature of -31 degrees until the fish is solid and storing at -4 degrees or below for 24 hours.
Since I don’t have the refrigeration equipment to do that, I buy high quality tuna already frozen into convenient bricks. Many supermarkets, like Whole Foods, carry them.

If the tuna is frozen, I let it thaw a little. If it has thawed, I return it into the freezer for about 10 minutes to firm up. That makes it easier to cut. I slice the tuna carefully into the smallest cubes I can make. Once done, I place the tuna in a bowl and put it back in the fridge until I’m ready to use it. If I feel the tuna is releasing a lot of water, I’ll put it on top of a paper towel in the fridge.
In a separate small bowl, I combine the soy sauce and the chili oil, and set it aside.
I finely chop the scallions, and set them aside.
Once the eggs have cooled, I peel them and cut them in half. I scoop out the yolks and place them in a bowl, starting with 1/4 cup of the mayonnaise, adding more if needed. I use a fork or whisk to get as many of the lumps out as possible. If I wanted to get serious, I could put them in a blender or food processor to make a creamy puree. An option is to place the puree in a piping bag and carefully squeeze it out into each egg half. I’d do that if I was serving guests. But otherwise, I simply use a spoon.
Once all the egg halves are filled, I place them on a plate and put them back in the fridge until ready to serve.
When it’s time to serve, I take the tuna out of the fridge, pouring the soy sauce/chili oil mix into the bowl with the tuna and I mix well. I let the tuna marinate for just 2 minutes, pouring off the excess marinade. I don’t want it to marinate too long, or it’ll get very salty.
I remove the plate of eggs from the fridge and carefully put a small spoonful of tuna on top of each one. I garnish with the sesame seeds and the chopped scallions and serve immediately.

It’s nice to have some crackers, toasted bread or even chips, on the side.