Cook the pasta. Bring a large pot of salted water to a boil.
Cook the pasta until just al dente. You want it tender but with a little bite, so it holds up in the salad.
Cool it down. Drain and rinse the pasta under cold water to stop the cooking. Shake off excess water well so it doesn’t water down the dressing.
Make the dressing. In a jar or small bowl, whisk together olive oil, lemon juice, red wine vinegar, Dijon, garlic, oregano, salt, and pepper.
Add lemon zest if using. Taste and adjust acid or salt as needed.
Prep the mix-ins. Halve the tomatoes, dice the cucumber, slice the onion, chop the herbs, and drain the tuna. If using olives and capers, pat them dry to keep the salad from getting too salty.
Toss the base. In a large bowl, combine the cooled pasta with tomatoes, cucumber, onion, olives, capers, and roasted red peppers.
Pour over about two-thirds of the dressing and toss to coat.
Add tuna and feta. Gently fold in the tuna and feta so the tuna stays chunky and the feta doesn’t crumble to dust. Add more dressing as needed.
Finish with herbs. Stir in parsley and dill. Taste and adjust with extra lemon, salt, or pepper.
The salad should taste bright, savory, and balanced.
Let it rest (optional but great). Chill for 20–30 minutes to let flavors meld. Give it a quick toss before serving and add a splash of olive oil or lemon if it looks dry.