Saute onions. Heat oil in a large frying pan over medium-high heat. Add onions and season with salt and pepper. Cook until translucent.

Simmer beans. Add remaining ingredients (including the 1/2 teaspoon kosher salt), stir to combine and bring to a boil. Reduce heat to a simmer, cover and let cook until beans are tender, but not mushy, about 10 minutes. Taste and add more salt and pepper if necessary.