Heat up the oil in a sauce pan. Add in the onion and sauté for 2-3 minutes until golden. Add in the ginger and garlic and sauté until fragrant, another 2-3 minutes. Add in the chili paste along with the tomato paste, mix well and sauté for 2 minutes. Add in the broth, vinegar, sugar and salt. Mix well and cook for another minute or two. Turn off the flame.