Heat a large skillet over medium heat. Add the olive oil and the onion and cook until soft. Add the garlic, cook for one more minute and add the spinach.
When the spinach is just wilted, stir in the quinoa and cook for 2 more minutes, stirring the whole time. Stir in the artichokes, olives, and white beans. When everything is heated through, season with salt and pepper, add the lemon juice, and stir before serving.