In a large skillet, heat the oil over medium-high heat; add the onion and cook, stirring, until golden, about 3 minutes. Add the pork and break it up with a wooden spoon; cook, stirring occasionally, until no longer pink, about 5 minutes. Sprinkle in the taco seasoning with 1/2 cup water and simmer, stirring, until saucy, 1 to 2 minutes. Remove from the heat.
Preheat the oven to 400 degrees . Lightly grease a round 9-inch deep-dish pie pan. Add 1/2 cup salsa to the bottom of the pan and tilt to coat. Arrange a third of the tortilla pieces on top, overlapping slightly to make an even layer. Top with half of the meat mixture and half of the peas, then sprinkle with 1/3 cup cheese. Add another layer of tortilla pieces, 1/2 cup salsa and the refried beans; sprinkle with the jalapenos and 1/3 cup cheese. Layer with the remaining tortilla pieces, meat mixture and peas; sprinkle with 1/3 cup cheese.
Cover the pan snugly with foil, set on a baking sheet and bake in the middle of the oven for 25 minutes. Uncover the pan, sprinkle the remaining 3/4 cup cheese on top and bake until bubbling, about 8 minutes. Tent with foil and let stand for 10 minutes. Uncover and top with the sour cream and cilantro.