Bring a large pot of salted water to a boil. Add the pasta and cook to al dente. Drain and set aside to cool. If you're in a hurry, rinse the pasta under cold water to cool it down quickly.
While the pasta is boiling, wash and chop the cherry tomatoes, cucumber, olives, basil and mint.
If you're using raw pumpkin seeds, dry roast them in a pan over low heat. Stir every 30 seconds to avoid burning. Roast for 3–5 minutes until they puff up slightly and turn golden brown. Set aside to cool. This step is optional.
In a small bowl, whisk together the pesto, olive oil, and lemon juice. You can also skip this step and add the dressing ingredients straight into the mixing bowl in the next step.
In a large bowl, combine the pasta, chopped veggies and herbs, pickled onions, pumpkin seeds and feta. Pour over the dressing (or add the pesto, olive oil, and lemon juice directly). Season with salt, pepper, and chili flakes. Toss everything until well combined. Taste and adjust seasoning if needed.
Optionally, you can top with additional herbs or pickled onions when serving.
Serve and Enjoy!