In a large bowl, mash chickpeas with a potato masher or pulse in a small food processor. Set aside.
Grate zucchini and carrots. Place in a clean dish towel or cloth.Squeeze out as much moisture as possible. Add the grated vegetables to the large bowl with the mashed chickpeas.
Add the panko, eggs, onion powder, salt, and pepper to the bowl with the mashed chickpeas and vegetables.
Stir until thoroughly combined and refrigerate for 30 minutes.
Heat avocado or olive oil in a large skillet over medium-high heat.
Scoop 2-3 tablespoons of mixture into your hand press to compress it into a patty.
Cook for 3-4 minutes, until the underside is golden brown, then flip and repeat.
Serve immediately with a dollop of plain Greek yogurt or sour cream and sliced green onion.