Den Backofen auf 220°C (200°C Umluft) vorheizen. Cut the cucumbers into thin slices. Combine 4Tbsp light vinegar, 1Tbsp sugar and ½tsp 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 2Tbsp of neutral oil, the cajun spice mix, ½tsp of salt and a large pinch of pepper. Bake in the oven for 20–25min., mixing halfway through baking.
Peel and halve the onions, then slice thinly. In a medium pan, heat up 1½Tbsp of neutral oil over medium heat. Add the onions with a large 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 large pan, heat up 1Tbsp 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 4Tbsp of mayonnaise, the sriracha sauce, and 2tsp vinegar. Thin with water as desired. Season to taste with salt and pepper.
Drain the cucumbers in a sieve, reserving 2Tbsp of the liquid in a salad bowl. Mix in 2Tbsp of neutral oil and a large pinch of salt and pepper to make a dressing. Cut the tomatoes 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.