Preheat oven to 390℉ . Combine lemon zest, lemon juice and paprika in a medium-sized shallow glass or ceramic dish. Add chicken fillets to dish and turn to coat. Cover dish with plastic wrap and leave to marinate for 10 minutes.
Meanwhile, set a large non-stick frying pan over a medium-high heat and spray with oil. Add eggplant and cook, stirring occasionally, for 5 minutes or until golden. Remove eggplant from pan and set aside.
Drain chicken of excess marinade. Return frying pan to a medium-high heat and spray with oil. Add chicken and cook each side for 1-2 minutes or until golden. Chop chicken roughly in pieces.
Spread cauliflower crusts with an even layer of tomato paste. Top crusts with chopped chicken, reserved eggplant, baby spinach and capsicum then scatter with mozzarella.
Place pizzas in oven and cook for 10 minutes or until cheese is bubbling and golden.
Cut pizzas in slices, garnish with extra lemon zest and parsley then serve.