1.Preheat oven to 200°C/180°C fan-forced. Line a large baking tray with baking paper. Steam or microwave potato until tender. Place in a large heatproof bowl; mash until smooth. While warm, add ham, corn, parsley, flour and parmesan; mix to combine. Season. Shape mixture into 8 equal-sized croquettes. Roll in breadcrumbs, then place on prepared tray. Spray with oil. Bake for 20 minutes or until golden.
2.Meanwhile, place tomato and beans in a saucepan over moderate heat. Cook and stir for 5 minutes or until heated and slightly thickened.
3.Serve beans with croquettes.
You can make croquettes a day ahead; keep, covered, in the fridge.