In a large mixing bowl, combine the drained chickpeas and artichoke hearts. Using a fork or potato masher, gently mash them together until they form a chunky mixture.
Next, stir in the chopped hearts of palm, vegan mayonnaise, Dijon mustard, green onion, kosher salt, Old Bay seasoning, and black pepper. Mix until everything is well incorporated.
Sprinkle the all-purpose flour over the mixture and gently fold it in to help bind the cakes together.
Using your hands, form the mixture into patties (about 2-3 inches in diameter). You should yield around 8-10 cakes.
Place the panko breadcrumbs on a plate and gently coat each patty with breadcrumbs, pressing lightly to ensure they stick.
In a large skillet, heat a generous drizzle of olive oil over medium heat.
Once the oil is hot, carefully add the crab cakes to the skillet. Fry for about 4-5 minutes on each side, or until golden brown and crispy.
Once cooked, transfer the cakes to a paper towel-lined plate to absorb excess oil. Garnish with additional chopped green onions before serving with vegan tartar sauce.