Wash, clean and halve the tomatoes. Peel and slice the onion. Peel garlic and chop finely. Wash the rocket, shake dry, clean and cut into bite-sized pieces.
Cook the pasta in boiling salted water according to the instructions on the packet. Spread a thin layer of oil on a coated pan, fry the onion for about 3 minutes while turning. After 2 minutes stir in tomato paste and garlic and fry.
Pour in broth and bring to the boil. Season to taste with salt, Sambal Oelek and sugar. Add tomatoes, tuna and capers and warm up briefly. Drain the pasta. Mix noodles, sauce and rocket and arrange on a plate.