Combine tomatoes, cucumber, onion, and olives in a large bowl.
In a small bowl, whisk together olive oil, balsamic, lemon juice, and salt and pepper. Pour over vegetables and mix well.
Crumble feta on top. You can use serve the salad on the side, or put it in the pita with the falafel.
For the falafel:
Working in batches, pulse swiss chard in a food processor until finely chopped, scraping down sides as you go. Chard should be very finely chopped but take care to not make it into a paste. Transfer to a bowl and continue until all chard has been processed.
Add chickpeas to food processor and pulse until coarsely ground. Add to bowl with chard.
Add garlic, tahini, cumin, salt, and pepper and mix well until evenly combined. Add flour, 2 tablespoons at a time, until mixture holds together and doesn't feel too wet.
Using your hands, form into 12-16 patties, depending on desired size.
Heat oil in a large pan over medium high heat. Working in batches, cook for 3 to 4 minutes on each side, until nicely browned.
Stuff into pita, top with some hummus and villager salad, and serve immediately.
Recipe by Things I Made Today at https://www.thingsimadetoday.com/2013/05/06/falafel-is-a-gateway-food-and-villager-salad-is-just-plain-delicious/