Step 1: Prep the Zucchinis - Preheat your oven to 375°F (190°C). Cut the zucchinis in half lengthwise, then scoop out the insides with a spoon, leaving a 1/4-inch border around the edges. Reserve the scooped-out flesh in a bowl, and place the zucchini boats in a non-stick baking dish. Sprinkle salt over each zucchini boats.

Step 2: Make the Filling - Heat the olive oil in a large skillet over medium heat. Add onion and garlic, and cook until the onion is soft and the garlic is fragrant. Add the diced tomatoes and cook for 5 minutes. Stir in the quinoa, pine nuts, feta cheese, and parsley. Season with salt and black pepper, to taste. Remove from heat.

Step 3: Stuff the Zucchini Boats - Spoon the filling mixture into the zucchini boats, pressing it down firmly with the back of the spoon and mounding it slightly. Sprinkle some more feta cheese on top of the filling.

Step 4: Bake the Zucchini Boats - Cover the baking dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for another 10 minutes, or until the zucchinis are tender and the filling is heated through.