Preheat the oven to 400°F and line a baking sheet with parchment paper.
In a food processor, combine the chickpeas, whole egg, egg whites, parsley, cilantro, chopped onion, and garlic cloves. Pulse until the mixture forms a coarse, slightly chunky paste.
Add the ground cumin, coriander, and baking powder. Pulse a few more times until well incorporated, being careful not to over-process; you want the texture to remain a bit rustic.
Scoop the mixture into small patties or balls (about 4-5 per serving) and place them on the prepared baking sheet. Lightly flatten them to form patties.
Bake for 20-25 minutes, flipping halfway through, until the falafel are crisp on the outside and heated through.
While the falafel bakes, prepare the tahini sauce by whisking together tahini, lemon juice, the extra garlic clove, and water (as needed) to achieve a smooth, pourable consistency. Season with a pinch of salt if desired.
Arrange the mixed greens on a serving plate, top with the crispy falafel, and drizzle generously with the creamy tahini sauce.
Serve immediately and enjoy your flavorful and satisfying meal.