In a food processor, pulse the cooked chickpeas, fresh parsley, and garlic cloves until the mixture reaches a coarse, crumbly texture.
Transfer the mixture to a medium bowl and stir in the egg whites, hemp hearts, ground cumin, sea salt, and black pepper until a thick, moldable dough forms.
Shape the mixture into 6 equal-sized patties, pressing them firmly between your palms so they hold their shape during cooking.
Heat the extra virgin olive oil in a large non-stick skillet over medium heat.
Carefully place the patties in the skillet and sear for 4 to 5 minutes per side until they are deeply golden brown and crispy on the outside.
While the falafel is cooking, whisk together the nonfat Greek yogurt, tahini, and lemon juice in a small bowl until the sauce is smooth and creamy.
Serve the hot falafel patties immediately, drizzled with the zesty tahini sauce.