Preheat oven to 350 degrees F (175 degrees C). Spray a baking sheet with cooking spray.
Sprinkle 1/4 teaspoon fajita seasoning over tilapia fillets and arrange on the prepared baking sheet.
Bake tilapia in the preheated oven until fish flakes easily with a fork, 15 to 20 minutes. Remove fish from oven and cut each fillet into 3 pieces.
Spray a skillet with cooking spray and add corn, black beans, and 1/8 teaspoon fajita seasoning; cook and stir over medium-high heat until heated through, about 3 minutes. Remove skillet from heat.
Spray a separate skillet with cooking spray and add pineapple; cook and stir over medium-high heat until lightly browned, about 2 minutes. Add onion to pineapple; cook and stir until heated through, about 1 minute more. Remove skillet from heat.
Pour 1 teaspoon olive oil in a large skillet over high heat; add 4 tortillas and cook until heated through, about 30 seconds per side. Remove tortillas from skillet and repeat cooking the remaining tortillas in the remaining oil.
Place a piece of tilapia onto each tortilla and top with corn mixture, pineapple mixture, cilantro, avocado, cabbage, sour cream and a squeeze of lime.