Cook edamame according to package directions; drain and rinse with cold water to cool.
Combine edamame, chickpeas, cilantro, cumin, coriander, 1/4 teaspoon garlic powder, and the salt in a food processor; cover and pulse until blended. Sprinkle in baking powder and flour, and pulse until mixture forms a ball. Wrap mixture in plastic wrap, and refrigerate at least 1 hour.
Use a 1 1/2-tablespoon scoop to portion out mixture (heaping scoops), and shape into patties (you should get 16 patties).
Heat oil in a nonstick skillet over medium heat. Add patties, and cook 2 to 3 minutes per side or until golden brown.
Stir together Greek yogurt, lemon juice, and 1/8 teaspoon garlic powder in a small bowl.
Fill tortillas with two falafel patties each, tomato, cucumber, and yogurt sauce.
To freeze uncooked patties, wrap individually in plastic wrap, and freeze in a zip-top plastic freezer bag up to 3 months. Let thaw in the refrigerator, and cook as described above.