Wash hands with soap and water.
Put beans and water in large pot and soak by the overnight or quick-soak method.
Cook until tender, about 2 hours. Add more water if necessary. Drain.
Slowly heat oil and sauté garlic and 1 onion until tender (5 to 7 minutes).
Mash cooked beans, sautéed vegetables, parsley, salt, lemon juice and hot pepper sauce until smooth.
With floured hands, form ovals with bean mixture (about 1/4 cup each). Roll in flour.
Fry falafel, with the remaining oil in skillet, until golden brown. Drain on paper towel.
Combine yogurt with remaining onion.
Serve falafel in pocket bread topped with yogurt.