Cook spaghetti in salted water according to the package. Once al dente, drain and rinse with cold water to bring its temperature down. In the colander, drizzle the pasta with olive oil and toss, to prevent it from sticking.
Thinly slice onion and lemon (be sure to remove the seeds). Also, using a mandoline (big time saver!) thinly slice the zucchini.
Use a large wok and heat the olive oil on medium-high heat. Add the sunflower seeds and fry them, stirring, for 3 to 4 minutes. Use a slotted spoon to remove the seeds and reserve.
In the same oil, add the sliced onion and lemon. Season with salt and pepper and fry until the onions begin to caramelize and the lemon has softened (this will take around 5 minutes)
Add capers, stir and let sizzle for 2 minutes.
Add the zucchini, some more salt and pepper, and cook until the zucchini have shrunk in size by about half and are translucent (about 12 minutes). By now, the entire kitchen should smell like a delicious, lemony sauce...
Turn off the heat and wait for one minute. Then, add the cooled down spaghetti and toss to coat.
Keep tossing while adding the chopped parsley, the sunflower seeds and feta cheese. Serve with some additional parsley for garnish.
TIP: if you prefer, you can remove the lemon peels as you eat. I myself LOVE its bitter tang, but it can be a bit overwhelming for some.
