Start by bringing a big pot of salted water to a rolling boil. Toss in the fusilli and let them twirl away until perfectly al dente—you want them springy, not mushy, so taste as you go. Once they're cooked, drain and rinse the pasta under cold water. That rinse isn't just for cooling; it keeps everything from sticking and helps the salad stay light. While the pasta cools, get your veg situation sorted. Dice the cucumber, bell peppers, and red onion finely so every bite feels colorful and even. Flake your tuna with a fork—don't mash it, just bust it up enough to spread evenly through the salad. Now, in a large mixing bowl, whisk together the mayonnaise, yogurt, rice wine vinegar, lemon juice, garlic salt, red pepper flakes, dillweed, plus a hit of salt and black pepper. Taste and adjust—some days you might want a touch more lemon zing or a heavier hand with dill. Add the cooled pasta, flaked tuna, all those crisp veggies, capers, and give it a gentle but thorough mix. You're looking for every spiral to pick up a coat of the dressing and plenty of 'stuff' in every forkful. Scoop some onto a plate and you'll see it: little flecks of dill, glossy pasta, pastel veggies, and that clean, briny note from the tuna. Cover and let it chill in the fridge—even a short stint gives the flavors time to meld.