Prep the aromatics. Finely mince red onion or shallot, and dice the celery.
Chop your herbs. Zest the lemon first, then squeeze the juice into a small bowl.
Make the dressing. In a mixing bowl, whisk together lemon juice, half the lemon zest, Dijon, olive oil, and your choice of Greek yogurt or mayo. Add a pinch of salt and pepper.
Taste and adjust acidity or creaminess as you like.
Flake the tuna. Drain the tuna well to prevent a watery salad. Add it to the bowl and use a fork to break it into bite-size flakes.
Add the crunch and herbs. Fold in celery, onion, fresh herbs, and capers if using. Add a small amount of garlic if you want extra punch.
Season and balance. Taste the salad.
Add more lemon juice for brightness, olive oil for richness, or yogurt/mayo for creaminess. Adjust salt and pepper.
Finish with zest. Sprinkle in the remaining lemon zest and give it one last gentle stir. The zest delivers a fragrant top note.
Chill briefly (optional). Let the salad rest in the fridge for 10–20 minutes.
This helps the flavors meld and the texture set.
Serve your way. Scoop over greens, pile onto toast, tuck into lettuce cups, or spoon over grains like quinoa or farro.