Preheat oven to 425 degrees. Coat a 13x9 baking dish with cooking spray. In a bowl, combine breadcrumbs, panko, 2 tbsp oil, parsley, lemon juice, garlic, oregano and zest.
Arrange tilapia in baking dish in single layer; top with shrimp. Sprinkle evenly with crumb mixture; drizzle with remaining 1 tbsp oil. Bake until tilapia and shrimp are opaque and cooked through, 10-12 minutes.
Coat large nonstick skillet with cooking spray. Add spinach; cook, stirring, until just wilted. Divide spinach among serving plates. Top with tilapia, shrimp and tomatoes.