In a small bowl, mash the avocado with the chopped cilantro and lime juice.
Gently stir in the diced Roma tomato and season with salt to taste.
Preheat your panini maker according to the manufacturer's instructions.
Spread a thin, even layer of spicy mustard over one side of each slice of sourdough bread.
Place one slice of bread mustard-side down on a work surface.
Layer the sandwich with one slice of Colby Jack cheese, two slices of blackened oven-roasted turkey, half of the avocado mixture, two more slices of turkey, and another slice of cheese.
Top with a second slice of bread, mustard-side up. Repeat to make the second sandwich.
Carefully place the sandwiches mustard-side down on the hot panini maker.
Close the panini maker and cook until the bread is crisp and golden, the sandwich is heated through, and the cheese is melted.
Remove carefully, slice if desired, and serve immediately while warm. This Spicy Southwestern Turkey Panini is best enjoyed fresh from the press.