Add the olive oil, onions, bell peppers, garlic, and salt to a pot and fry the mixture over medium heat until the onions are soft and are starting to brown (10-12 minutes).
Add the Romano beans and continue frying the mixture while you chop the tomatoes.
Add the tomatoes and curry powder, and cover the pot with a lid. Turn down the heat and let the green beans simmer for 25-30 minutes or until the beans are nice and tender.
To finish the curry, put the yogurt in a bowl and scoop in some curry. Stir the mixture together, adding a little curry at a time until the mixture is warm. This tempers the yogurt by bringing its temperature up. Then you can pour the mixture back into the pot and stir it together.