Drain both cans of tuna really well—like squeeze it in a strainer for a full minute to get the liquid out. If you leave excess water, your tuna salad recipe ends up watery no matter what. Pat it dry with paper towels if you're being extra careful (yes, really). This step takes 2 minutes but makes a huge difference in the final texture.

Combine mayo, Greek yogurt, and lemon juice in a large bowl and whisk until smooth. The Greek yogurt shouldn't have any lumps mixed in—break it up completely. This creamy base comes together in about 1 minute. Taste it and adjust lemon juice to your preference because everyone likes different levels of tang.

Add the dry mustard powder to the mayo mixture and stir well. This seems like such a tiny amount, but it changes everything about the flavor profile. You're adding warmth and complexity without it tasting like mustard—it's just a secret depth. Mix for about 30 seconds until it's completely incorporated.

Fold the drained tuna into the mayo mixture using a spatula or fork. Break up any large chunks as you go but don't pulverize it into paste—you want some texture. This takes about 2 minutes total. I always gently fold rather than stir aggressively to keep the tuna pieces intact.

Add the diced celery, red onion, dill pickles, and fresh parsley to the bowl. Fold everything together until the vegetables are evenly distributed throughout. Don't skip the parsley because it adds freshness that balances the richness of the mayo. The whole mixing process takes about 3 minutes.

Stir in the toasted breadcrumbs and sunflower seeds last, just before serving. These two ingredients are game-changers for texture—they stay crunchier if you don't add them too early. The breadcrumbs soak up a tiny bit of moisture while keeping things crispy. Mix gently for about 1 minute.

Season with a pinch of salt and black pepper, then taste and adjust as needed. Most people forget this final seasoning step, but it wakes up all the flavors. Let the tuna salad sit in the fridge for at least 15 minutes before serving so flavors meld together nicely. The texture improves even more after a couple hours.