Season chicken thighs with the garlic salt and pepper, and cook on the grill until cooked through (about 5-7 minutes per side on medium heat with the lid closed. However, all grills are different, so check frequently). Allow chicken to rest for 5 minutes, then dice into bite-sized chunks.
Put the can of beans into a pot and cook until heated through. Drain and rinse beans; set aside.
Heat a large griddle over medium heat. Place tortillas on the griddle (making sure not to overlap), and sprinkle with cheese, a spoonful of pinto beans, and some of the chicken pieces. When the tortilla is warmed through and the cheese has melted, remove from the griddle and top with an avocado slice, some cabbage salsa and a squeeze of lime juice. Serve immediately.