Rinse the quinoa under cold water until the water runs clear.
In a medium pot, combine quinoa, 2.5 cups water, and salt; bring to a boil, then cover and simmer for 15 minutes until water is absorbed; fluff with a fork.
While the quinoa cooks, brush the sliced zucchini, bell pepper, and onion with 3 tablespoons of olive oil and grill over medium-high heat until tender and charred; set aside.
In a blender or food processor, combine fresh basil, 1/4 cup olive oil, lemon juice, and garlic until smooth to create the dressing.
In a large bowl, combine the cooked quinoa, grilled vegetables, feta, sun-dried tomatoes, and olives.
Drizzle the lemon basil dressing over the salad and toss gently to combine.
Serve warm or chilled.