In large pot, bring vegetable broth to a boil. Stir in couscous. Reduce heat to low, cover, and let stand until liquid is absorbed, about 13 minutes. Fluff couscous with a fork. Transfer to a bowl and let cool completely.
Dice tomato and set aside.
Slice cucumber in half lengthwise, then again. Slice into thin pieces and set aside.
Dice onion into small pieces and set aside.
Mince dill and parsley and set aside.
Make Simple Balsamic Vinaigrette according to recipe instructions.
To the bowl of couscous, add diced tomato, diced cucumber, diced red onion, dill, parsley, dressing, and top with feta cheese.