Rinse the chickpeas thoroughly and pat them very dry with a paper towel to ensure the falafel stays crispy.
In a food processor, combine the chickpeas, egg whites, hemp hearts, garlic cloves, fresh parsley, cumin, coriander, sea salt, and black pepper.
Pulse the mixture until a coarse, uniform paste forms, being careful not to over-process into a smooth purée.
Form the chickpea mixture into 4 to 6 small, flat patties using your hands.
Heat the olive oil in a large non-stick skillet over medium heat.
Place the patties in the skillet and cook for 4 to 5 minutes per side until they are golden brown and firm to the touch.
While the falafel cooks, whisk together the Greek yogurt, tahini, lemon juice, and garlic powder in a small bowl until the drizzle is smooth.
Serve the warm falafel patties immediately, topped with a generous portion of the lemon-tahini drizzle.