In a mortar and pestle or a coffee grinder reserved for grinding spices, combine the cumin, cloves, allspice, and peppercorns. Grind until cracked but not pulverized, then transfer to a small dish and add the bay leaves, oregano, and cinnamon. In a large heavy skillet, heat the olive oil over medium heat. Add the onion and carrots and cook, stirring occasionally, until the onion is softened, about 5 minutes. Stir in the garlic and chiles and cook for 2 minutes more. Add the vinegar, fish broth, and all the spices to the pan, cover and reduce the heat to medium-low. Simmer for 10 minutes. Transfer to a glass bowl and let stand at room temperature for 1 to 2 hours, for the flavors to marry. When ready to serve, return the mixture to the skillet and add the oysters. Over medium-low heat, bring the mixture just up to a gentle simmer and let the oysters cook very gently for about 3 minutes (the oysters are done when the edges curl and they turn almost white do not overcook). Remove from the heat and adjust the seasonings, adding more salt and vinegar if desired. Remove the bay leaves and cinnamon stick and serve in deep bowls, scattered with the fresh cilantro.

Note: Fresh chiles and bell peppers can be roasted over a gas flame or on a tray under the broiler. Keep turning so the skin is evenly charred, without burning and drying out the flesh. Transfer the charred peppers to a plastic bag, tie the top closed and let steam until cool to the touch, about 15 minutes. (If you are rushed, you can place the bag in a bowl of iced water to speed things up.)

The best way to peel is just to pull off the charred skin by hand and then dip the peppers briefly in water to remove any blackened bits. Do not peel the pepper under running water since that will wash away flavorful juices. Once peeled, cut away stems, seeds and veins.