Cook the pasta. Bring a large pot of salted water to a boil. Cook the pasta until just al dente.
You want it a touch firm so it holds up in the salad.
Rinse and cool. Drain the pasta and rinse briefly under cold water to stop the cooking and remove excess starch. Shake off excess water well.
Make the dressing. In a large bowl, whisk together the lemon zest (from both lemons), 1/4 cup lemon juice (add more to taste), olive oil, vinegar, Dijon, garlic, honey, salt, pepper, and a pinch of red pepper flakes if using.
Toss the pasta. Add the cooled pasta to the dressing and toss to coat while it’s still slightly warm. This helps the pasta absorb flavor.
Add the veggies and herbs. Fold in cucumber, tomatoes, red onion, olives, parsley, and dill.
Taste and adjust with more lemon juice, salt, or pepper as needed.
Finish with cheese. Gently fold in the feta. If using mozzarella, add it now as well.
Rest, then serve. Let the salad sit for at least 15–20 minutes so the flavors meld. Serve slightly chilled or at cool room temperature.