Soak whole, dry beans (I often use kidney beans but black or pinto beans are fine) overnight (6-8 hours). Process until they are coarsely ground to within 1/8th of their original size. Depending on the beans, 1 to 1.25 cups of dry beans should be sufficient for getting at least 2 cups soaked beans. Any remaining soaked beans over 2 cups in quantity can be refrigerated or frozen for repurposing in a later recipe.
Soak 2 tbsp of dry chia seeds in 1/4 cup of warm water
Put up to 3 cups of vegetables in a large bowl. I used 1 cup each of carrots, red cabbage and broccoli for this post. Add the coarsely ground beans and salt to the bowl and combine with a spatula.
Except for the water, add the remaining ingredients, including the now-gelatinous chia seed mixture, and combine with a spatula.
Let the mixture rest for 10 minutes to allow the salt to draw out moisture from the vegetables. Add water 1/4 cup at a time (mixing each time) until you achieve a mixture that is moist but not wet.
Form the moist (but not wet) mixture into patties ( I use 1/3 cup for each). Note: The patties will bind more loosely than typical burger patties during this step. Don't worry. The steaming process will bring these together nicely.
Place the patties into a steamer about 1/4" apart. They don't expand noticeably during the cooking process.
Bring the water in the steamer to a boil and cook for 15 minutes. Let the burger patties rest for 5 minutes and then remove somewhat gently with a heat-safe spatula and onto a serving platter.
The burgers are now ready to serve and will continue to bind as they cool. By the time you assemble these into burgers with toppings, etc. they will have excellent structural integrity.
Be sure to bring these to room temperature or lower (~20-30 minutes) before grilling or pan-cooking them any further to get the typical 'charred' look.