Boil the beans until just tender. Season with salt, pepper and extra-virgin olive oil. Reserve.
In a heavy pot, slowly saute the garlic in the olive oil for 10 minutes. Add the carrot and celery and saute slowly for another 15 minutes.
Add 1 cup of water and reduce rapidly for 5 minutes. Over high heat, add the mussels, cover and steam until they open. Remove them, shell them, reserve them. Boil the liquid in the pot for another 15 minutes.
Mince the cherry tomatoes. Toss with fresh oregano.
Boil the orecchiette until just al dente.
When ready to serve, warm the tomato in the liquid for 1 minute. Add the beans, the shelled mussels, and the orecchiette. Toss together. Season with salt and pepper and extra-virgin olive oil. Serve immediately.