Preheat the oven to 325ºF. (162.778°C)
Measure the rolled oats, rice flour, and baking powder into a mixing bowl and whisk till combined. Add the crumbled bleu cheese and crushed tomatoes and stir till combined.
Make a well in the flour, and add the canola oil. Mix on medium speed using a paddle attachment until crumbly. Add the water all at once, and mix until dough forms and all the ingredients are combined.
Turn the dough out onto a slightly floured surface and form it into a log, about 2 inches in diameter. Wrap in plastic wrap and chill for 1 hour.
When ready to bake, slice the biscuits 1 ⁄ 8 - inch thick and place them on a parchmentlined cookie sheet. Bake 12– 15 minutes until they are dry and firm to the touch.
Turn off the oven and leave the biscuits in the oven another 20– 30 minutes. Remove them from the oven, cool them on a baking rack, and store them in a cookie tin.