Heat the olive oil in a pan over medium heat. Saute the diced onion for 5 minutes until soft, then add the garlic for 1 minute. Stir in the tomato puree, tomatoes, oregano, sugar, salt, and pepper. Simmer on low heat.
Mix the chicken mince, grated parmesan, breadcrumbs, egg, garlic powder, oregano, Italian seasoning, salt, and pepper until well combined.
Spread about 1 tablespoon of the chicken mixture onto one side of each mini tortilla in a flat layer.
Heat olive oil in a large pan over medium-high heat. Place 2-4 tortillas chicken-side down and press gently. Cook for 3-4 minutes until golden and crispy, then flip.
Spread the tomato sauce thinly on top, add the mozzarella and parmesan, add 1 tbsp water, and cover with a lid to melt the cheese.
Remove from the pan and repeat with the remaining tortillas. Toss the rocket with olive oil and lemon juice, then top each taco with the rocket and extra parmesan.