Drain and rinse the 15-ounce can of chickpeas. Drain the 15-ounce can of artichoke hearts and the 15-ounce can of hearts of palm; roughly chop the hearts of palm if not already chopped.

In a large bowl, mash the chickpeas, artichoke hearts, and chopped hearts of palm with a fork or potato masher (or pulse 1–2 times in a food processor) until the mixture is flaky but not pureed.

Add 3 tablespoons vegan mayonnaise, 1 1/2 tablespoons Dijon mustard, 2 tablespoons chopped green onion, 1/4 teaspoon kosher salt, 2 teaspoons Old Bay seasoning, and 1/4 teaspoon black pepper to the mashed mixture. Mix until evenly combined.

Stir in 3 tablespoons all-purpose flour and 3/4 cup panko breadcrumbs. Mix until the mixture holds together when pressed; if it seems very loose, let it sit 5–10 minutes to allow the breadcrumbs to absorb moisture.

Form the mixture into evenly sized patties about 1/2-inch thick, placing them on a plate or baking sheet as you go.

Heat a skillet over medium heat and add enough olive oil to coat the bottom of the pan.

Fry the patties in batches, without overcrowding the skillet, for about 3–5 minutes per side, or until each side is golden brown and crispy. Adjust heat as needed to prevent burning.

Transfer cooked patties to a paper towel-lined plate to drain any excess oil. Serve topped with additional chopped green onion and vegan tartar sauce on the side for dipping.