Put the peanuts in a big bowl. In a small cup, mix the salt in the hot water and stir until the salt dissolves. Sprinkle this over the peanuts and toss to coat them well.
Lay the nuts on a tray and bake in a preheated oven at 180 C for about 25 minutes (stirring every 10 minutes or so). They should be slightly soft when you get them out as they continue to cook after they come out of the oven.
While they are roasting, melt the butter. Mix the honey and add in the cayenne pepper or red chilli powder (if you want a spicier flavour).
Once the peanuts come out of the oven, let them cool slightly (you can have them this way if you want them plain). Pour them into a bowl and drizzle the honey/butter mixture over them. Toss until all are well coated. Sprinkle the granulated sugar over them and put them back on the oven tray. (I prefer to place aluminium foil on the tray at this point to reduce the work of cleaning the tray later)
Bake again for about 10-15 minutes, stir once or twice in between. Take the tray out and pour the peanuts in a bowl, they will be slightly sticky. Whilst they are still hot, sprinkle the icing sugar over them and keep stirring with a spoon or tossing. This helps reduce the stickiness and gives them a sweet coating.
Now let them cool until they become nice and crispy. You can store them in an airtight container for a couple of weeks (if they will even last that long!).