Rinse the quinoa in a fine mesh sieve until the water runs clear.
Add the quinoa, plus 4 cups water, to a medium saucepan. Bring the quinoa to a boil then reduce the heat to low and simmer for 25 minutes (uncovered), or until the germ ring is visible (indicating the quinoa is cooked). Transfer the quinoa to a large bowl to cool.
Whisk together the garlic, cilantro, lime zest, lime juice, salt, pepper and olive oil in a small bowl. Set aside.
Dice the avocados and tomatoes into bite-sized pieces. (See Kelly's Notes.)
Add the diced avocado, tomatoes and onions to the quninoa. Drizzle with dressing and fold to thoroughly combine.
Serve salad at room temperature or refrigerate and serve cold.