In a sauce pan, heat oil over medium heat. Add jalapeno, serrano, onion, garlic and salt. Cook until onion is translucent. Add blended tomato, sugar, pepper and vinegar.
Cover with a lid, reduce heat to low, and simmer for 10 minutes. Remove from heat, stir, taste and correct seasonings if needed.
This salsa can be made in advance and freezes beautifully.