Dice the cucumber and bell pepper into uniform 1/4-inch pieces—this consistent sizing ensures even texture throughout the salad. Finely dice the red onion and mince the garlic as small as possible so the flavors distribute evenly without overpowering any single bite. Pit and slice the olives, and chop the fresh dill if using. Having everything prepped and ready before mixing ensures you can work quickly and the vegetables stay crisp.

In a large mixing bowl, combine the Greek yogurt with the freshly squeezed lemon juice and minced garlic. Stir well to fully incorporate—the lemon juice will brighten the yogurt and prevent it from tasting flat. I find that whisking these together first creates a smooth, well-seasoned base that coats everything evenly when the other ingredients are added.

Drain the canned tuna thoroughly and break it into bite-sized chunks as you add it to the yogurt mixture. Add the prepared cucumber, bell pepper, red onion, and olives from Step 1, then gently fold everything together using a spatula or large spoon. Be careful not to overmix—you want the tuna to stay in nice chunks rather than becoming mushy. Fold in the crumbled feta cheese and fresh dill last.

Taste the salad and season with salt and freshly ground black pepper as needed. Start conservatively—you can always add more salt, but you can't take it back. I recommend using freshly ground black pepper over pre-ground, as it provides a much brighter, more complex pepper flavor that complements the Mediterranean ingredients beautifully. Serve immediately or chill until ready to eat.