Heat the oil in a frying pan, add the pancetta and sauté for 5 mins or until golden and the fat has run out. Add the garlic and tomatoes, sauté for 2 mins, then add the chilli, wine and sugar. Cover and simmer for 5 mins. Place the watercress on a board and use a knife to very roughly chop it and then place in a colander.
Cook the gnocchi in boiling water. Drain the gnocchi in the colander, pouring it on top of the watercress. Leave to drain for 1 min before tossing into the hot sauce. Serve topped with a little more watercress and parmesan shavings.