To make salsa, heat the oil in a medium skillet over medium high heat.
Add the onions and the garlic and cook stirring occasionally, until the onion is soft, about 2 minutes. Add the tomatoes, serrano chile and oregano. Stir in the cumin and Worcestershire sauce, season with salt and pepper. Lower the heat to medium-low and simmer for 10 minutes until tomatoes are cooked through. Let cool slightly and puree in a blender.
Place the corn husks in warm water; soak for 30 minutes, or until they're soft and pliable.
While the husks soak, stir together the chicken, cheese, cilantro, frozen vegetables, roasted red peppers and 2 cups salsa in a bowl. Add the corn oil and cornmeal mix; stir until combined.
Remove 2 corn husks from the water. Tear into 12 thin strips for tying up the tamales; set aside.
Unfold a soaked husk, wide-end up, on a work surface. Starting at the top edge, spoon 2/3 cup filling down the center and mold into a 4-by-2-inch rectangle, leaving room at the bottom for folding.
Roll up the tamale jelly roll-style to enclose the filling. Fold up the bottom end of the husk and tie with one of the strips of husk. Repeat with the remaining husks, filling and ties.
Add 1 inch of water to a deep pot with a tight-fitting lid; place a steamer basket in the pot. Arrange the tamales upright (closed-end down) in the basket. Bring the water to a boil over medium-high heat; cover and steam the tamales for 25 minutes, adding more water as needed.
Carefully remove the tamales from the steamer and let stand for 5 minutes. Transfer to a platter; untie and open the husks, then garnish the tamales with chopped fresh cilantro.