Julienne the pancetta, peel and crush the garlic clove and peel and finely chop the onion.
Heat the olive oil in a pot (medium/tall walls), add the pancetta, and cook until the fat gets translucent (medium heat). Add garlic and onion, and sauté a few minutes until golden.
Remove the garlic and add the beans and 1/2 teaspoon of salt. Add passata and mix.
Add the pasta and the water and cook 10-15 minutes, or until the pasta is cooked "al dente". Give it a mix every now and then to avoid pasta sticking to the bottom. If needed, add a little water to end the cooking.
You can add chili to the pasta, but I prefer to serve Pasta e Fagioli with a bottle of chili oil or freshly crushed pepperoncino on the side; this way, each one can add to personal tastes.
I'm not sure if you should serve Pasta e Fagioli with a tablespoon or a fork, I usually begin with the fork and end up with the spoon (all those juices), so I set them both on the table.