Combine quinoa and chicken stock in a small saucepan and bring to a boil. Cover and reduce heat to simmer. Cook for 20 minutes. Remove from heat and set aside to cool.
Combine diced cucumber and tomato in a bowl. Sprinkle with salt and stir. Let sit 10 minutes.
Cut off the thick bottom stems from the parsley. Using a food processor, finely chop the parsley one bunch at a time, including the mint leaves in one of the batches. Transfer to a medium mixing bowl.
Pour off and discard the juice that has accumulated in the bottom of the cucumber and tomato bowl and add them to the parsley. Add the green onion and cooled quinoa. Stir well to combine.
Wisk together the garlic, lemon juice, and olive oil in a small bowl. Pour over the salad and stir well.
