I also added finely chopped lettuce, their recipe didn't call for that.  The only other suggestion I have is to cut way down on the onion if you use red onion, they were potent and made me feel like I had heartburn!
Oh, their recipe also called for roasted red pepper, which I didn't have.  You just chop everything up and mix with a can of drained garbanzos.  It's nice and fresh tasting!

Ingredients

• 15 oz Chick Peas
• 1/2 cup Red Onion
• 1 cup Iceburg Lettuce
• 1/2 cup Celery
• 4 tomatoes Grape Tomato
• 2 tbsp Parsley
• 2 tsp Garlic
• 3 tbsp Lemon Juice Raw
• 1 tsp Extra Virgin Olive Oil
• 1/8 tsp Salt

Directions

Mix all together, let marinate for 10 minutes.