Preheat the oven to 375 degrees F. Line a sheet pan with parchment paper or a silicone liner.
In the bowl of a food processor, add the beans/chickpeas and pulse them for 30 seconds until they are combined and start to form a batter.
Add the onion and garlic and pulse for another 15 seconds.
Add the eggs, cumin, salt, and pepper and pulse for a final 15-20 seconds until all ingredients are incorporated.
Pour in the bread crumbs and oats and pulse just until they incorporate into the batter.
Divide the mixture into 6 portions with your hands, form them into round patties, then place them on the prepared pan, pressing them down gently with your palm so they're burger-shaped.
Bake the burgers for 30 minutes, flipping half way through until they're lightly crisp on the edges and lightly browned.
Serve the burgers hot on buns with the avocado slices, lettuce and tomato. Use ketchup and mustard or any other toppings if desired.