In a food processor, blend about half the chickpeas with the lemon juice until smooth. Add remaining chickpeas, red onion, garlic, cilantro, parsley, cumin, chili powder, salt, baking powder, and tahini. Process entire mixture until coarsely ground.

Shape burgers into 6 patties, about 4 ounces each. Refrigerate until firm.

Meanwhile, prepare the relish. Cut peppers in half, remove stems, and scrap out the seeds. Place in a microwave-safe bowl and cover tightly with plastic wrap. Microwave on high 7-8 minutes, remove from microwave, but leave plastic wrap on bowl 1-2 more minutes.

Remove plastic wrap and let peppers sit until cool enough to work with. Gently peel off the skin and dice peppers.

In a medium saute pan, combine diced peppers, apple cider vinegar, and sugar. Cook over medium-high heat until vinegar is reduced and relish has slightly thickened, about 3 minutes. Transfer to a bowl and refrigerate until ready to use.

Turn Air Fryer on to 350 degrees F. Coat the basket of your air fryer with cooking spray. Add falafel patties in a single layer (you may have to cook in batches), and lightly coat with cooking spray. Air fry 12-14 minutes, flipping halfway through, until golden brown and crispy.

Serve each patty on a bun and top each with about 2 tablespoons relish.