In a 4-quart sauté pan, heat most of the olive oil over medium heat, reserving ¼ cup for later.
Add the onions and sauté until soft and translucent; about five minutes.
Add the garlic and cinnamon, if using. Sauté until fragrant; about one minute.
Add the potatoes, tomatoes, one teaspoon sea salt, and some black pepper. Stir until everything is combined.
Add in the water and let come to a gentle boil. Top with green beans and sprinkle with a little more salt and black pepper.
Cover, reduce heat to medium-low, and let simmer for 30 minutes.
Remove lid and stir in the softened green beans.
Cover again and let simmer an additional 10-15 minutes, or until the potatoes are cooked through and beans are very tender.
Remove lid and stir in the parsley. Let cook an additional three minutes.
Remove from heat, taste, and adjust seasoning with salt and pepper to your liking.
Drizzle in the rest of the olive oil.
Serve with feta and good crusty bread.