In a 3- to 4-quart pan over medium-high heat, frequently stir oil, onion, and garlic until onion is lightly browned, 8 to 10 minutes. Add oregano, cumin, and allspice and stir until fragrant, about 30 seconds. Remove from heat.
Meanwhile, in a blender, purée chipotles (for less heat, remove seeds), small can (10 oz.) chili sauce, and tomato paste until smooth. Add to onion mixture.
Add remaining can (28 oz.) chili sauce to onion-chipotle mixture and stir to blend well. Season to taste with salt.
Note: Nutritional analysis is per 1/4 cup.