1.Preheat oven to 240°C/475°F. Line two large oven trays with baking paper.
2.Process kale, in two batches, until finely chopped. Return kale to processor; add 2 cups of the mozzarella, the eggs and breadcrumbs. Process until a sticky dough forms. Divide dough in half. Spread dough over trays to make two 22cm x 32cm (8¾in x 12¾in) rectangles.
3.Bake bases for 20 minutes. Turn bases over and bake for a further 5 minutes or until edges are browned.
4.Meanwhile, to make dill and horseradish cream cheese, combine all ingredients in a medium bowl.
5.Spread cream cheese mixture over bases. Top with onion and remaining mozzarella. Bake for 10 minutes or until cheese is melted and golden.
6.Top pizzas with smoked salmon, avocado and rocket. Serve with lemon wedges.