Pour the oil into a large oven-save pot and heat it over medium-high heat. Cook the onion for 2-3 minutes, then add the sausage and cook until browned.
Add the halved cherry tomatoes and diced pepper to the pot and continue cooking for another 2-3 minutes. Stir in the diced tomatoes, Italian herbs and season to taste. Simmer for 2 minutes, then stir in the beans, gnocchi, spinach and cheese.
Fill the empty can of diced tomatoes with water and pour it into the pot. Resist the urge to stir too much, because it will make the outside of the gnocchi mushy. Just make sure that all gnocchi are covered with sauce.
Bake, uncovered, for 15 minutes or until bubbly.
Note: This will make a fairly sauce-y dish. If you prefer to have it a little thicker, only add half a can of water instead of a full one. Also: The longer you leave the finished dish to stand, the thicker it will get.