Preheat the oven to 400 °F and line a baking sheet with parchment paper.

In a food processor or powerful blender, combine the chickpeas, ½ of the onion, garlic, ½ cup of the parsley, ¼ cup of the olive oil, cumin, teaspoon baking powder, salt, and pepper. Process until the mixture becomes a thick paste.

Add in the oats and process again until smooth.

Using your hands, gently roll the mixture in heaping tablespoon-sized balls (be careful not to over handle them). Place them on the baking sheet on bake for 25-30 minutes, until crispy and lightly golden on the outside.

While the falafel is baking, prepare the salad. Finely the dice cucumbers, tomato, remaining red onion and parsley. Drizzle with the remaining ¼ cup of olive oil and lemon juice. Add salt and pepper and mix to combine.

Prepare the pitas: fill each pita with tzatziki, chopped salad and 2-3 falafel.