In a medium bowl, combine the couscous and salt. Pour the boiling water over the couscous, cover with a lid or plastic wrap, and let it sit for about 5 minutes until the water is absorbed.
Fluff the couscous with a fork and stir in the olive oil and lemon juice. Allow it to cool to room temperature.
In a large bowl, combine the cherry tomatoes, cucumber, bell pepper, red onion, feta cheese, and parsley.
Add the cooled couscous to the vegetable mixture and gently toss to combine. Season with salt and pepper to taste.
Serve immediately or refrigerate for 30 minutes to let the flavors meld.