Preheat the oven to 400°F. Line a baking sheet with parchment paper.
In a food processor, combine the chickpeas, parsley, cilantro, onion, garlic, cumin, coriander, baking powder, salt, black pepper, olive oil, and lemon juice. Pulse until the mixture is well combined but still slightly chunky.
Transfer the mixture to a bowl and stir in the whole wheat flour until fully incorporated.
Using your hands, form the mixture into small balls or patties, about 1.5 inches in diameter, and place them on the prepared baking sheet.
Bake for 20-25 minutes, flipping halfway through, until golden brown and crispy.
While the falafel bakes, prepare the tahini sauce. In a small bowl, whisk together tahini, lemon juice, water, garlic, and salt until smooth. Adjust the consistency with more water if needed.
Serve the baked falafel warm with tahini sauce drizzled on top.