Remove the stems from the parsley and mince either by hand or with quick pulses in a food processor. The parsley should be finely chopped, but if you use a food processor be careful not to puree it. The parsley should form a fluffy base for other textures.
Chop the olives, walnuts, and green onions by hand into a rough dice. Dice the prepared tomatoes and drain.
Combine all of the chopped ingredients in a large wooden bowl. Add the olive oil, lemon juice, cumin, and red pepper flakes and toss to combine. Add salt and pepper, to taste.
*To toast nuts: Place nuts in a dry saute pan over medium heat. Toast, while shaking the pan to avoid overheating in 1 spot. Remove from the heat after 3 to 5 minutes when the nuts have achieved a nice pale golden color.