Toast the rice in a dry saucepan over a medium heat. Allow it to toast until a medium brown with a nutty scent, about 5-7 minutes. Once cooked, remove from the heat and allow to cool. Once cool, grind to a relatively fine powder in a spice grinder or a mortar and pestle. Set aside.
Heat the oil in a large skillet over a medium heat. Once warmed, add the ginger, galangal, lemongrass and spring onion greens. Cook for a minute or so until the mixture is verdant green and fragrant. Add the water and the ground rice and stir to combine, cooking for an additional minute or so.
Add the crumbled tofu and stir to incorporate. Add the Tamari or dark soy and stir again until the mixture is a uniform light brown colour. Taste for salt levels, as the mixture can be easy to over-salt with the vegan fish sauce. If you feel good about it, add the fish sauce. If it's already salty enough, omit it and save it for the dipping sauce. Add a little extra water if you'd like the larb to be a bit more juicy/
Add the brown sugar, some white pepper and chilli powder if you're using it, and stir to combine. Finally, add the makrut lime zest and stir again to combine. Taste for seasoning and adjust if necessary.