Finely chop your parsley by hand, discarding the stems. I typically just chop where most of the stems begin and don't worry about the thinner stems at the top.
If you have time, let your parsley rest on a plate covered in paper towel in your fridge. You can even do this overnight - this allows the parsley to dry and take the flavours of the lemon and oil.
Chop your mint, these do not have to be chopped as finely as the parsley
Finely chop your red onion and tomatoes.
Zest half a lemon, and juice two lemons.
Press any remaining moisture out of your quinoa, and add to the bowl of parsley, mint, tomatoes, and onion. Add your lemon zest and mix thoroughly. Then add your olive oil and lemon juice and toss.
Salt and pepper to taste - then serve!