Preheat the oven to 375°F
Toss the zucchini with 1 teaspoon salt and let wilt in a colander for about 10 minutes.
Press handfuls of the zucchini over the sink to extract most of the juices and transfer to a large bowl. Add the onion, oats, feta, pepper, dill, and mint. Combine and add the eggs, one at a time, mixing well with your hands or with a large spatula. Add the olive oil and stir well.
Lay a piece of parchment paper on a baking sheet and drizzle with olive oil. Sprinkle with a few sunflower seeds, and carefully pour over the zucchini mixture. Spread and level the surface with a spatula, drizzle with olive oil, and sprinkle with the rest of the sunflower seeds and the grated cheese.
Cover loosely with aluminum foil and bake for 30 minutes. Remove the foil and bake another 10 to 15 minutes, until the mixture is set and deep golden on top.
Let cool on a rack at least 20 minutes. Cut into pieces and serve warm or at room temperature.