Rinse and drain chickpeas and edamame, then pat them very dry with a paper towel.
In a food processor, pulse the chickpeas, edamame, hemp hearts, nutritional yeast, parsley, cilantro, cumin, garlic powder, salt, and pepper until a coarse, moldable dough forms.
Form the mixture into 4 small patties, pressing firmly so they hold their shape.
Heat avocado oil in a non-stick skillet over medium heat and sear the patties for 4-5 minutes per side until a golden-brown crust develops.
In a small bowl, whisk together the Greek yogurt, tahini, and lemon juice, adding a teaspoon of water to reach a pourable consistency.
Plate the hot falafel and drizzle generously with the lemon-tahini sauce before serving.