Heat the oil in the pot over medium-high heat, add the onions and cook for about 2 minutes until wilted, stirring all the time. Add the garlic and cook for 1-2 minutes. Reduce heat to medium low. Mix in the green beans, the salt, cinnamon and black pepper, and continue cooking for 2 minutes. Cover and cook for 10-15 minutes until beans are half tender, gently stirring occasionally.

Gently stir in the chopped tomatoes and tomato paste. Sprinkle with a little salt to release tomato juice. Cover and bring to a boil over medium-high heat. Reduce heat to medium-low and cook for about 20 minutes, or until tomatoes are broken and beans are tender. Uncover and continue cooking for about 10 minutes to thicken the sauce a bit.

Transfer to the serving bowl and eat warm or cold with pita bread.