Pat the sardines dry with paper towels, sprinkle with salt, and cut into 3cm pieces.

Thinly slice the onion into 5mm slices and mince the garlic.

Boil water in a pot, add salt, and cook spaghetti according to package instructions. Drain well.

Heat olive oil, garlic, and chili in a frying pan over low heat until fragrant. Add sardines and cook over medium heat.

Add onion to the pan and sauté until softened.

Add diced tomatoes, water, and salt to the pan. Simmer for about 5 minutes until thickened.