Prepare a hot fire in a charcoal grill or heat a gas grill or broiler to medium-high or 400 F.
In a small bowl, stir together the chili powder, oregano, paprika, coriander and garlic powder. Dredge the pork pieces in the seasonings, coating completely.
Place the pork strips and onions in a cast-iron pan or grill basket. Grill or broil at medium-high heat, turning several times, until browned on all sides, about 5 minutes.
To serve, spread an equal amount of pork strips and onions on each tortilla. Top each with 1 tablespoon cheese, about 2 tablespoons tomatoes, 1/2 cup shredded lettuce and 2 tablespoons salsa. Fold in both sides of each tortilla up over the filling, then roll to close. Serve immediately.