Heat the olive oil in medium-large saucepan or Dutch oven over medium-high heat. When hot, add the onions and a pinch of salt, and cook until softened and translucent, 7 to 10 minutes. Add the bell pepper, ginger, and garlic, and cook a few minutes more, until the pepper is just beginning to soften. Stir in the spices, stock, tomatoes, collard greens, salt, and pepper to taste, and mix well. Bring to a boil, then cover, reduce the heat to low, and simmer for 20 minutes.
Add the cannellini beans, and let simmer, covered, for an additional 10 minutes to allow the flavors to blend. Taste, adjust salt and pepper as needed, and serve.