Preheat the oven to 425 degrees. Brush a sheet pan with olive oil to prevent sticking. Pat tilapia dry, salt and pepper each side of the filet to taste and lay in the sheet pan. Brush the tops of each filet liberally with pesto. Top each filet with additional Parmesan cheese and place the sheet pan in the oven for around 15 minutes, or until the fish flakes easily and in no longer translucent.
For tomato and avocado salad: Gently combine tomatoes, diced avocado, 2 tbsp olive oil, and the juice from half a lemon. Salt and pepper to taste. Serve with the tilapia for an easy fresh side!