Preheat the oven to 400 degrees F. Line a sheet pan with parchment paper.
Toss the tomatoes with 1 tablespoon olive oil, 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper on the pan. Arrange them in a single layer, cut side up. Roast the tomatoes for 25-30 minutes until they are wrinkle but still juicy.
Make the quinoa while the tomatoes are in the oven. Combine the quinoa and water in a medium saucepan. Bring to a boil, reduce heat to low and simmer for 12 minutes until the quinoa is cooked and has absorbed the water. Remove the quinoa from the heat. Let stand covered for 5 minutes. Then fluff it with a fork.
To make the vinaigrette, whisk the garlic, mustard, 1/2 teaspoon kosher salt, 1/4 teaspoon black pepper, red wine vinegar and 1/4 cup olive oil in a small bowl.
In a large bowl, combine the quinoa, roasted tomatoes, chickpeas, cucumbers, olives, onions, walnuts, feta and parsley.
Pour the vinaigrette into the salad and stir to combine. Transfer into a serving bowl and top with additional feta and parsley as desired.