In a food processor, pulse the cooked chickpeas, hemp hearts, egg white, parsley, cilantro, garlic, cumin, coriander, salt, and pepper until a coarse, moldable paste forms.
Divide the mixture into four equal portions and shape them into thick, round patties.
In a small bowl, whisk together the non-fat Greek yogurt, tahini, and lemon juice until the sauce is smooth and well combined.
Heat the olive oil in a non-stick skillet over medium heat.
Add the falafel patties to the skillet and cook for 4-5 minutes per side until they are golden brown and develop a crisp exterior.
Serve the warm falafel immediately with the lemon-tahini yogurt sauce drizzled over the top or on the side for dipping.