Make the burgers:
In a large bowl, mash the potatoes and then add the beans and mash them coarsely. Don't smush the beans into a paste because you want some texture.
Add all of the remaining ingredients and mix well. Very clean hands are the best way to get in the bowl and make sure all of the flavor's spread all around.
Form the beans into patties. I made six hefty patties, but you can shape them smaller if you have a mind to.
Spray a nonstick griddle with some oil spray and when hot, grill the patties over medium-high heat until brown-black spots appear. Flip over and grill the other side.
Make the naan buns:
Use this recipe to make the naan bread dough. Break off enough of the dough to form a one-inch ball.
On a lightly floured surface, roll out the naan slightly larger than the diameter of your burger (you want to do this because the dough can spring back a little)
On a very hot griddle, spray some oil and grill the naan on each side until golden-brown spots appear. The naan will rise and become a little puffy on the griddle, which is great.
Make the coriander raita:
Blitz all of the raita ingredients in a blender until smooth.
Assemble the burger:
Slather on some of the coriander raita on the naan bun, layer on some leafies, onions and tomatoes, if you please, and the burger patty. Eat.