In a small bowl, whisk together the Greek yogurt, extra virgin olive oil, Dijon mustard, lemon zest, lemon juice, minced garlic, fresh parsley, fresh dill, black pepper, sea salt, and red pepper flakes until smooth and well combined. Set the dressing aside at room temperature. While the dressing rests, prepare all vegetables: peel and dice the cucumbers, finely mince the shallot, drain the capers, and measure out the arugula or sprouts. I like to make the dressing first so the flavors can meld slightly while you prepare everything else.
Bring a large pot of salted water to a boil and add the penne pasta, cooking according to package directions. About 3-5 minutes before the pasta finishes cooking, add the asparagus pieces to the pot. In the final 2 minutes of cooking, stir in the frozen peas. The vegetables will cook perfectly in this brief window and retain their vibrant color and slight crunch.
Drain the pasta and vegetables in a colander, then rinse thoroughly with cold water to stop the cooking process and remove excess starch. Transfer the cooled pasta and vegetables to a large mixing bowl and drizzle with 1 tsp olive oil, tossing gently to coat. Let the mixture cool for 5-10 minutes to reach room temperature before continuing.
Add the diced cucumbers, minced shallot, drained capers, and arugula or sprouts from Step 1 to the cooled pasta mixture in the bowl. Toss everything gently to combine, distributing the vegetables evenly throughout. I find it's best to add these fresher ingredients after the pasta has cooled so they maintain their crispness and don't wilt from any residual heat.
Pour the dressing from Step 1 over the salad and stir gently but thoroughly, making sure the creamy dressing coats all the pasta and vegetables evenly. Finally, tear the smoked salmon into bite-sized pieces and fold them gently into the salad just before serving, being careful not to break apart the delicate salmon. The gentle folding at the end keeps the salmon pieces intact and prevents them from getting mushed into the dressing.