Preheat oven to 375 degrees. Place all ingredients for falafel (except for the pitas, baking powder, and nonstick spray) in a food processor, and give them a good chop.
Transfer into a bowl, add the baking powder and stir together. Using a potato masher, mash any big chunks that remain – Mixture should remain slightly chunky, not smooth.
Spray a baking sheet thoroughly with olive oil nonstick spray. One at a time, take spoonfuls of mixture in your hands and form 15 balls, each about the size of a ping pong ball, and gently place them on the baking sheet. Spray the top of each ball with olive oil nonstick spray, for a total of about a 2-second spray.
Bake in the oven for 15 minutes. Meanwhile, combine 2 parts hummus to 1 part water, and stir until blended (add more water to taste depending on how watery you like your sauce). Season to taste with salt / black pepper and refrigerate until ready to serve.
While your falafel patties are baking, chop your veggies and warm up your pita bread.
Remove baking sheet from the oven, and carefully turn each ball over, gently reshaping if the bottoms have flattened.
Return to the oven and bake for an additional 10 – 15 minutes, until golden brown and slightly crispy. Allow to cool and set for at least 5 minutes. Note: You can also make these in the air fryer! To make in the air fryer, follow steps 1-3 above. After you spray the falafel with cooking spray, roll them in whole wheat or panko breadcrumbs for a light coating. Then air fry the falafel at 350 degrees F for 8 minutes. Flip and air fry for another 6 minutes on the second side.
Cut the whole pitas into halves, fill with spinach, 3 falafel balls, diced tomato, and top with spinach and sauce. Enjoy!