For the smoked pork tenderloin cooked at low temperature, first smoke the meat. To do this, place a pasta strainer in a pasta pot and heat it, smoke two handfuls of smoked flour or shavings in it, place the trimmed fillet in the strainer, close it tightly with a lid and wrap it with kitchen foil, then smoke it at medium heat for about 30 minutes.
Place the meat on a baking rack and let it roast in a preheated oven at 70-120 °C until the meat reaches a core temperature of 67-68 °C (takes several hours). Before serving, cut into thin slices. If the meat is at room temperature, use the following rule of thumb: roast at 80 °C for one hour per kilogram of meat, 1 1/2 hours with bones.
For the salsa, peel and seed the cucumber and cut into small cubes, finely ring the green onion, coarsely chop the cilantro, squeeze one lime, cut the second into fillets. Mix all ingredients well and season with olive oil, salt and pepper.
Cut the watermelon into thick bars and put them in the fridge until they are ice cold, then rub them with a little olive oil and sear them on all sides, season with lime juice and coarse salt.
Serve the smoked pork tenderloin cooked at low temperature with cucumber-cilantro salsa and fried watermelon.