Remove the strings from snap peas, place them in a microwave-safe bowl, cover loosely with plastic wrap, add 1 tbsp water, and microwave for 30 seconds to 1 minute. Rinse under cold water and drain. Slice diagonally.

Mince the onion and soak in water for about 5 minutes, then squeeze out excess water. Cut boiled eggs into wedges.

Mix all dressing ingredients (tuna, onion, mayonnaise, ponzu soy sauce, salt, and pepper) in a bowl.