Prepare an ice-water bath. Place eggs in a medium saucepan. Add enough cold water to cover eggs by about 1 inch. Bring to a boil. Cover, and remove from heat. Let stand 13 minutes. Drain, and transfer eggs to ice-water bath until cold.

Peel eggs, and halve lengthwise. Transfer yolks to a medium bowl, and mash with a fork until smooth. Stir in mayonnaise, wasabi, vinegar, and scallions. Season with salt. Pipe or spoon filling into whites. Garnish with pea shoots or sprouts.

For burgers:
Fit a food grinder with a grinding plate with about 1/4-inch holes. Grind tuna into a bowl. Add garlic, ginger, lemon zest, mustard, salt, and pepper. Mix gently, and shape into four 1-inch-thick patties. Cover, and refrigerate until cold and firm, about 30 minutes.

For coleslaw:
Whisk vinegar, sugar, and salt in a small bowl. Mix carrot, radish, cabbage, scallion, and sesame seeds in a medium bowl. Toss slaw with vinegar mixture, and refrigerate up to 1 hour.

Heat oil in a large nonstick skillet over medium heat. Cook patties to medium-rare, about 2 minutes per side. Wipe skillet clean, and return to heat. Spread mayonnaise on cut sides of roll halves, and heat, mayonnaise side down, until golden, about 1 minute. Divide burgers and slaw among bottom halves of buns. Sandwich with top halves.

*These delicate patties will fall apart if cooked directly on the grill.