Cover sun-dried tomatoes with 4 cups boiling water in a bowl; let stand 30 minutes or until soft.
Heat oil in a large saucepan over medium-high heat. Add onion and garlic; sauté 4 minutes or until onion is tender. Place tomato mixture, onion mixture, vinegar, sugar, paste, and salt in a blender; process until smooth. Place pureed tomato mixture in pan. Bring to a simmer over medium heat; partially cover, reduce heat, and simmer 30 minutes, stirring occasionally. Chill thoroughly.
Note: Store in refrigerator for up to a week.