In a medium pot, heat your olive oil on medium and add in the onion and bell pepper to saute until they soften. Stir in the garlic and chili pepper flakes and season with salt to taste.
Pour in the beans and broth and bring to a boil. Lower the heat to a simmer and cook for 15 minutes. Remove from the burner and mix in the lemon juice and dill. Portion out the soup to serve in your bowl and top with some crumbled feta.