Bring a large pot of salted water to a boil. Score a small X into the bottom of each tomato and place in the boiling water. Blanch for 1 minute. Remove the tomatoes with a slotted spoon and place them into a large bowl filled with ice water until cool to the touch. Gently peel with a small knife, starting at the X. Dice the tomatoes. Saute half of the minced garlic and onion in in olive oil a pan until onion is translucent, then add in the tomatoes, about 1 Tbs. olive oil and continue to cook over medium heat, stirring occasionally until tomatoes begin to break down and become saucy, about 10-15 minutes season with salt and pepper to taste. Set sauce aside.
Preheat oven to 400 degrees.
Pulse cauliflower in a food processor until finely shredded (you may need to do it in batches). If you don’t have a food processor, a cheese grater works well, too. Use a paper towel to press the cauliflower and remove any moisture.
In a large bowl combine the cauliflower, eggs, almond flour, a couple pinches of salt, pepper, the rest of the minced garlic and oregano. Stir thoroughly until it is all combined.
Transfer to a parchment-lined (and greased!) baking sheet and press into a pizza shape about ⅓’’ thick. Make sure to form a crust!
Bake at 400 degrees for about 20 minutes.
Meanwhile prepare the prawns. Remove the legs and any roe. With your thumb, push one side of the shell off the meat. This should break the underside of the shell and allow you to get your thumb between the meat and exterior. Be careful. Sometimes the tails can be prickly. Gently work your way around the outside of the meat, separating as you roll the tail around. Pinch the base of the tail to push the remaining meat out from the shell.
In a small bowl combine prawns with 1 Tbs. olive oil, sliced garlic and pepper flakes.
Remove crust from oven and spread sauce over evenly. Top with prawns. Cook in the oven for another 10-15 minutes until crust is golden.