In a small bowl, mix the ground flaxseed with 2 tbsp water. Stir to combine and set aside to thicken for 10 minutes.
In a large bowl, mash the black beans by hand until they are broken down.
Add the flaxseed and all other burger ingredients except salt, pepper and oil to the bowl, and mix with your hands to combine. Check the taste and season with salt and pepper if needed (I found I needed to add quite a bit of salt, even with the tamari).
Divide the mixture into 4 balls, and shape these into burger patties.
Heat a generous amount of oil in a large frying pan on a medium heat. Cook the burgers for 4-5 minutes on each side until browned.
Serve immediately on your favourite burger buns with vegan mayo, lettuce leaves, tomato slices and microgreens (optional). Enjoy!