Finely chop the onion. Roughly chop the tomatoes and garlic. Put them in the blender or in the beaker of the hand blender. Add the remaining ingredients for the pizza sauce and blend to create a smooth sauce.
Drain the tuna, halve the cherry tomatoes and slice the mozzarella. Spread the wraps with pizza sauce. Divide the tuna, cherry tomatoes and mozzarella over the wraps.
Place the wraps on a baking tray lined with baking paper. Bake the wraps in the oven for about 8 minutes until golden brown or until the mozzarella has melted.
Cut the avocados all the way around the stone. Twist the two halves apart. Remove the stone, scoop the flesh out of the skin and cut into thin slices.
Divide the avocado over the wraps. Season with salt and pepper to taste.