Combine the quinoa and water in a small saucepan over high heat and bring to a boil. Cover and reduce heat. Simmer on low until the quinoa is cooked and has absorbed the water, about 12-15 minutes.
Remove the quinoa from the heat. Let stand covered for 5 minutes. Then fluff it with a fork.
Preheat a gas or charcoal grill on high heat.
Rub the corn with 1 teaspoon olive oil. Grill, turning occasionally, until lightly charred, about 5-7 minutes. Let the corn cool slightly before slicing off the kernels.
In a large bowl, combine the corn, blueberries, onions, arugula, feta and chives. Stir in the quinoa.
For the dressing, whisk together the garlic, mustard, lemon juice, olive oil, salt and pepper in a small bowl.
Drizzle the dressing into the salad, tossing to coat.