Take flattened rice/poha in a bowl and rinse it once or twice. Soak it in water for 5 minutes. Using a strainer, drain all the water from the poha. Keep it aside.
Pour the kidney bean/rajma into the blender and make a coarse paste.
Heat oil in a non-stick pan over medium flame. Add chopped garlic and saute for a minute.
Add chopped onion and cook until it is translucent.
Add the chopped tomatoes and pour salt. Mix it well.
Add coriander powder, red chilli powder and black pepper powder. Give it a nice mix. Cook until it no longer smells raw and oil begins to separate.
Add chopped coriander leaves and green chillies. Give it a mix and turn the flame off.
Pour this spice mix into the kidney bean paste. Mix it well.
Then add the soaked flattened rice into the bowl and mix it well. Place the bowl in the freezer for 30 minutes to set.
Heat oil in a non-stick pan over medium flame. Divide the bean mixture into 4 parts. Wet your hands and form 4 large patties. Place the patties in the pan and cook until both sides are golden and crisp.
Toast the buns in the same pan and then place them on a plate.
Serve the patties on the buns topped with peri-peri mayo, tomato and onion slices. You can add any other desired toppings. Enjoy!