Open and drain the canned tuna thoroughly. Place tuna in a medium mixing bowl and gently flake with a fork until mostly broken up but still slightly chunky.

Make spicy dressing

In a small bowl, whisk together mayonnaise, Greek yogurt, Sriracha, Dijon mustard, soy sauce, rice vinegar, sesame oil, and honey until smooth and homogenous.

Pour the dressing over the flaked tuna. Add black pepper and salt. Fold gently with a spatula or fork until tuna is evenly coated. Taste and adjust heat/salt: add up to 1 more teaspoon Sriracha for more spice or more mayo/yogurt to mellow.

Vegetables & Crunch

Add the diced celery, red onion, and half of the sliced scallions to the tuna mixture. Fold gently to combine. The celery provides crunch and the onion sharpness; adjust quantities to taste.

If using cilantro, stir it in now along with the toasted sesame seeds. Reserve a pinch of scallions and sesame seeds for garnish.

To Serve

Place mixed greens or individual lettuce leaves on a serving platter or divide among 4 plates.

Spoon the spicy tuna salad over the greens or into lettuce cups. Arrange avocado slices alongside or on top if using.

Garnish with the reserved scallions and sesame seeds. Serve with toasted bread, crackers, or pita on the side and lime wedges for squeezing over just before eating.

Leftovers: store in an airtight container in the refrigerator for up to 2 days. If packed with avocado, expect the avocado to brown sooner; add fresh avocado when serving if preferred.