In a saucepan over medium-high heat, combine the quinoa and water and bring to a boil. Reduce the heat to low, cover, and cook for 15 minutes, or until the water is absorbed. Set aside, covered, to steam for 5 minutes. Fluff the quinoa with a fork and transfer to a bowl. Cover and refrigerate for at least 1 hour, or until chilled.
In a small bowl, whisk together the oil, lime juice, salt, and pepper.
Add the corn, avocado, tomatoes, and black beans to the quinoa and stir to combine. Add the lime dressing and stir gently. Refrigerate for 30 minutes before serving.