Layer 2 (15-inch) sheets of heavy aluminum foil together and fold 1/4-inch of the edges together to create 1 sheet. Repeat with another 2 pieces of foil, to create 2 double foiled sheets. Bend the edges of 1 of the sheets up 2 inches, to help keep the liquid in the foil.
On a double sheet of foil, layer (in this order), the oil, onions, jalapeno, red bell peppers, chicken, salt and pepper, garlic, cilantro, cheeses, lemon juice and tequila.
Put the second, double layered foil sheet on top of layered ingredients. Fold both double layered sheets of foil together in 1/4-inch folds, 4 times. When all the sides are folded together, make sure that the pouch is not leaking. Refrigerate until ready to cook.
To cook preheat the oven or grill to 250 degrees F. Remove the foil pouch from the refrigerator and put on the grill, being careful not to snag the foil pouch and tear it open. Grill for 10 minutes, then flip and cook for another 10 minutes.
Remove the pouch from the grill and slice the bag open. Garnish with the tomatoes, cilantro, and Parmesan and serve on warmed rolls.