Preheat the oven to 425°F (220°C).
Remove the leaves and stem of the cauliflower and cut it into small florets.
Place the cauliflower florets on a baking sheet and drizzle with 2 tablespoons of olive oil. Season with salt and pepper. Toss to coat evenly.
Roast the cauliflower in the preheated oven for about 20-25 minutes, or until golden brown and tender, stirring halfway through.
While the cauliflower is roasting, prepare the dressing. In a small bowl, whisk together the remaining olive oil, lemon juice, dried oregano, salt, and pepper to taste.
In a large mixing bowl, combine the roasted cauliflower, cherry tomatoes, cucumber, red onion, Kalamata olives, parsley, and feta cheese.
Pour the dressing over the salad and toss gently to coat all ingredients evenly.
Adjust seasoning if needed and serve immediately or chill in the refrigerator for 30 minutes before serving for a refreshing taste.