Den Backofen auf 220°C (200°C Umluft) vorheizen. Cut the cucumber into thin slices. Combine 2Tbsp light vinegar, 1½tsp sugar and a large pinch of salt. Add the cucumbers and let sit until ready to serve.
Die Kartoffeln samt Schale in ca. 2cm breite Spalten schneiden oder der Länge nach vierteln. On a lined baking tray, mix the potatoes with 1Tbsp of neutral oil, the cajun spice mix, a large pinch of salt and a pinch of pepper. Bake in the oven for 20–25min., mixing halfway through baking.
Peel and halve the onion, then slice thinly. In a small pan, heat up 1Tbsp of neutral oil over medium heat. Add the onions with a pinch of salt and sugar and cook covered for ca. 4min., stirring occasionally. Then remove the lid and continue cooking for 4–6min., until the onions are softened and caramelised.
In a medium pan, heat up ½Tbsp of neutral oil over high heat. Add the minced meat. Break the meat up with a wooden spoon, then flatten it on the bottom of the pan, letting it get nicely browned and slightly crispy on the edges, 8–10min. Stir only a few times, making sure to let it get as crispy as possible. Drain any excess grease, if desired.
In a small bowl, combine 2Tbsp of mayonnaise, the sriracha sauce, and 1tsp vinegar. Thin with water as desired. Season to taste with salt and pepper.
Drain the cucumbers in a sieve, reserving 1Tbsp of the liquid in a salad bowl. Mix in 1Tbsp of neutral oil and a pinch of salt and pepper to make a dressing. Cut the tomato into thin wedges and toss in the dressing with the lettuce and cucumbers. In a serving bowl, add the oven fries and top with the mince, the lettuce mix, and the onions. Drizzle with the sriracha sauce, then serve.