In a large frying pan, warm together the olive oil, sage leaves, and garlic.
Add the sausages and brown lightly on all sides, about 10 minutes.
Add the beans, crushed tomatoes, and ground chili (if you are using).
Simmer, uncovered, stirring gently every so often for about 15 minutes.
Adjust the seasoning with salt and pepper.
Spoon the beans onto a warmed oval platter.
Lay the sausages on top and serve.