To make the Filling: Fire roast the poblano pepper over an open flame on the range, turning occasionally with tongs until the skin is evenly blackened and burnt. Place blackened poblano in a heatproof bowl, cover with plastic wrap and set aside until cooled. Remove skin, stalk and seeds from blackened poblano. Chop finely.
To make the Sauce: Preheat a cast iron skillet on medium heat. Toast the Guajillo chilies in the preheated skillet for about one minute, pressing down with a spatula until they are aromatic. Remove from the pan into a heat-proof bowl and cover with warm water to rehydrate. Set aside.
Turn the heat under the cast iron skillet up to medium high. Once heated, add the unpeeled onion, garlic and tomato. Cook, turning with tongs, until the skins are toasted and showing black spots, about 3 minutes for the garlic and about 10 minutes for the onion and tomato. Remove to a heat-proof bowl and cover with plastic wrap for a few minutes.
Remove the skin from the onion, garlic and tomato. Coarsely chop the onion and tomato and add them, along with garlic and rehydrated roasted Guajillo chilies, to a food processor. Pulse with a little of the roasted Guajillo soaking liquid to achieve a smooth sauce. Season to taste with salt and pepper and lime juice, set aside.
To make the Fricos: Wipe the surface of a non-stick skillet with a little vegetable oil on a paper towel and place over a medium-low heat for about two minutes until evenly heated. Sprinkle 4 ounces of the Dry Jack Cheese in an even layer to form two circles, each about three inches in diameter. Cook, adjusting the heat as needed to keep the cheese bubbling but not burning.
When the cheese has just melted together and is bubbling in the center, add two ounces of the filling to the center of one the fricos and continue cooking until the fricos are still pliable, the bottom is an even golden brown and the filling is warmed through. Cover the frico that has the filling with the other frico and lightly press down the edges to seal. Set aside in a warm oven. Repeat for the remaining frico.
To plate: Place the sauce in a small dipping bowl. Garnish with two cilantro sprigs, half a finely sliced radish and a lime slice.
