Use your grill to make this quick, easy, and delicious meal. (No grill? Use a grill pan instead.)
Heat a grill to high. Clean and lightly oil hot grill. Alternately thread fillets, tomatoes, and onion onto eight 8-inch skewers. Brush kebabs with olive oil; season with salt and pepper. Grill until fish is opaque throughout, 6 to 10 minutes, turning occasionally.
In a large bowl, toss together zucchini, 1 tablespoon oil, corn kernels, lemon juice, and mint. Season with salt and pepper and serve with kebabs.