Meanwhile, heat oil in a large pot over medium-low heat. Add onion and ½ teaspoon salt; cook until softened, stirring frequently so onion does not brown, 5 minutes. Add garlic and cook, stirring, until fragrant and soft, 2 minutes. Add tomato paste and cook, stirring, until slightly dark in color, 2 minutes. Add Sungold or cherry tomatoes, chipotle, 1 teaspoon salt, 6 cups water, and bay leaves. Let simmer, stirring, until most of the tomatoes soften and begin to burst, 10 minutes. Remove and discard bay leaves.
