To make the falafel

1. One day in advance: Place the dried chickpeas and baking soda in a large bowl filled with water to cover the chickpeas by at least 2 inches. Soak overnight for 18 hours (longer if the chickpeas are still too hard). When ready, drain the chickpeas completely and pat them dry. Add the chickpeas, herbs, onions, garlic, and spices to the large bowl of a food processor fitted with a blade. Run the food processor 40 seconds at a time until all is well combined forming the falafel mixture.
2. Transfer the falafel mixture to a container and cover tightly. Refrigerate for at least 1 hour or (up to one night) until ready to cook.
3. Just before frying, add the baking powder and sesame seeds to the falafel mixture and stir with a spoon.
4. Scoop tablespoonfuls of the falafel mixture and form into patties (1/2 inch in thickness each). It helps to have wet hands as you form the patties.
5. Fill a medium saucepan 3 inches with oil. Heat the oil on medium-high until it bubbles softly. Carefully drop the falafel patties in the oil, let them fry for about 3 to 5 minutes until crispy and medium brown on the outside. Avoid crowding the falafel in the saucepan, fry them in batches if necessary.
6. Place the fried falafel patties in a colander or plate lined with paper towels to drain. Serve falafel hot next to other small plates; or assemble the falafel patties in pita bread with tahini sauce (or hummus), arugula, tomato, cucumbers, and pickles.

To make the tahini sauce

1. With a mortar and pestle, crush the garlic cloves with the salt into a paste (or mince the garlic and season with salt.)Add the crushed garlic, tahini paste, and lime juice to the bowl of a food processor and blend (it will be thick as it emulsifies.) Add a little bit of water and blend again until you reach the desired consistency.
2. Transfer tahini to a serving bowl, and if you like stir in fresh chopped parsley.