Place the cucumber on a cutting board and lightly bash it with the flat side of a large knife or a rolling pin until it splits open and softens. Cut the smashed cucumber into bite-sized chunks. Thinly slice the spring onion. Roughly chop the peanuts.
Toss the cucumbers, spring onions and peanuts with ½Tbsp vegetable oil, ½Tbsp vinegar and a pinch of sugar and salt. Set aside to marinate.
Quarter and deseed the paprika, then cut into large cubes.
Halve the bread horizontally. Preheat a medium-sized pan on medium-high heat. Working in batches, toast the bread halves in the dry pan on each side for ca. 45sec. Keep the pan on the heat and set the bread aside. Tip: You can also heat the bread in an airfryer for 30–45sec. at 200°C, or in a microwave for 30–34sec. at 700W).
Heat ½Tbsp of vegetable oil in the same pan over medium-high heat. Pat the meat dry. Season with salt and pepper. Cook it for ca. 3min. until starting to brown. Add the paprika and sauté for ca. 4min. Once the meat is cooked through, stir in 2Tbsp water, 1Tbsp honey, ½Tbsp mustard, 1tsp vinegar, ¼ of the madras powder. Cook for ca. 30sec., then turn off the heat. Season to taste with salt.
Assemble the sandwiches by spreading a total of 2Tbsp mayonnaise on the insides. Then fill the sandwiches with the chicken curry. Season the salad to taste and serve alongside the sandwiches.