1. Combine all falafel ingredients except oil in the bowl of a food processor fitted with a steel blade. Pulse mixture until coarsely ground.
2. Transfer to a bowl or container and refrigerate, covered, for several hours.
3. Form the falafel mixture into balls about the size of walnuts and press to flatten.
4. Heat 4 inches of oil to 375 degrees F in a deep pot or deep fryer. Fry about 6 balls at once for about 4 minutes, or until golden brown.
5. Drain on paper towels.
6. Stuff each pita with 4 falafel balls, chopped tomatoes, lettuce, and tahini.
Makes 4 servings, Difficulty: Easy