Prep the zucchini: Preheat oven to 400°F (200°C). Slice zucchini lengthwise.
Use a spoon to scoop out the centers, leaving about 1/4-inch walls to form “boats.” Chop about half of the scooped flesh and set aside.
Par-bake the boats: Place zucchini halves on a lined baking sheet. Brush with 1 tablespoon olive oil and season with salt and pepper. Bake for 10 minutes to soften slightly.
Remove and set aside.
Sauté the aromatics: In a skillet over medium heat, warm 1 tablespoon olive oil. Add red onion and a pinch of salt. Cook 3–4 minutes, until translucent.
Stir in garlic and cook 30 seconds until fragrant.
Build the filling: Add the chopped zucchini flesh, oregano, cumin, and red pepper flakes. Cook 3–4 minutes to reduce moisture. Stir in rice, chickpeas, cherry tomatoes, sun-dried tomatoes, olives, and capers.
Warm through.
Brighten and season: Turn off the heat. Mix in lemon zest, lemon juice, parsley, and nuts if using. Taste and adjust salt and pepper.
The filling should be punchy and well-seasoned.
Stuff the zucchini: Spoon the filling into each par-baked zucchini boat, packing gently. Mound the tops slightly.
Bake to finish: Return to the oven and bake 12–15 minutes, until the zucchini is tender and the tops are lightly crisp at the edges.
Garnish and serve: Top with vegan feta and extra parsley. Add a final squeeze of lemon or a drizzle of good olive oil.
Serve warm.