Heat a large saut� pan over medium heat, and add olive oil. Add diced onion, and cook until translucent, about 2 minutes.
Add garlic, and cook 1 minute. Add beans, and cook until hot and slightly softened, about 3 minutes. Add the spinach and vinegar, stirring frequently until spinach is wilted, about 3 minutes. Add the thyme, and season with the salt and pepper. Serve.