Slice the eggplants in half lengthwise and scoop out the insides, leaving about a 1/2-inch shell. Set the scooped-out eggplant flesh aside.
Brush the eggplant halves with olive oil and sprinkle with salt. Place them cut-side down on a baking sheet and roast in the oven for 20 minutes until tender.
Meanwhile, finely chop the reserved eggplant flesh. In a large skillet, heat the remaining olive oil over medium heat. Add the chopped eggplant flesh, red bell pepper, and zucchini. Sauté for about 5-7 minutes until softened.
Stir in the cooked quinoa, chickpeas, sun-dried tomatoes, olives, oregano, smoked paprika, salt, and pepper. Cook for an additional 5 minutes until everything is heated through.
Remove the eggplant shells from the oven and carefully flip them cut-side up. Fill each half generously with the quinoa and vegetable mixture.
Return the stuffed eggplants to the oven and bake for another 15-20 minutes until everything is heated through and slightly golden.
Once done, remove from the oven and let them cool for a few minutes.
Garnish with fresh parsley and crumbled feta cheese if using.