Soak clams in a large bowl of cold water for 10 minutes, change water and soak again for another 5 minutes. Rub clams together lightly to remove any excess sand.
Meanwhile, In a large sauté pan, cook the pancetta over medium heat until fat has rendered and the cubes are starting to crisp; About 5 minutes. Add the yellow pepper and the onion to the pan along with a pinch of salt and pepper, stir and cook for about 3 minutes. Add the chopped jalapeño and the garlic, stir and cook for about 2 minutes. Add the lime juice, stir.
Drain the clams and add them to the pan, stirring to coat; about 2 minutes. Add the tequila to the pan and cover with the lid. Let the clams steam for about 5-7 minutes or until they have opened. Discard any clams that did not open.
Divide the clams between four bowls and top with the jalapeño slices and parsley. Serve with lime wedges.