Heat the oil in a frying pan, and add the onion and pepper. Cook over a medium heat for a couple of minutes, until slightly soft. Add the garlic and green beans, and cook for 2 more minutes.
Next add the cannellini beans, smoked paprika and turmeric, and mix to coat. Turn the heat down to low. Pour in the rice, vegetable stock, and plenty of black pepper. Mix carefully once to make sure everything is evenly distributed, then stop stirring. Arrange the artichoke hearts and olives on top of the paella, and cover with a lid. Leave to cook over a low heat for around 25-30 minutes, or until the rice is fully cooked. Serve topped with a drizzle of extra virgin olive oil, a squeeze of lemon juice, and some fresh parsley.
Don't be tempted to stir the paella as it's cooking - you're not making risotto. Just leave it to cook and you'll hopefully end up with some nice crispy bits on the bottom.