In a medium pot, add uncooked quinoa and 2 cups water. Bring to a boil, cover, reduce heat to simmer, and cook for 15 minutes.
After quinoa has cooked, fluff with a fork and add to a large bowl.
Chop parsley, mint, and red onion then add to bowl with quinoa.
Remove seeds from tomatoes. To remove seeds from the tomatoes, lay tomato on a cutting board so the stem faces the side. Cut the tomato in half. Using a spoon, scoop out the seeds and liquid.
Chop tomatoes and add to large bowl with quinoa.
Cut cucumber in half and scoop out the seeds.
Chop cucumber into small pieces and add to bowl with quinoa.
Zest lemon and add to bowl with quinoa.
Add lemon juice, salt, pepper, and red pepper flakes to bowl with quinoa.
Make Simple Balsamic Vinaigrette according to recipe instructions.