Preheat oven to 350°F.
Cut the jalapeños into a boat cut. (Click the link above to see how to do a Canoe Cut.)
Sprinkle insides of cut jalapeños lightly with salt and pepper, to taste.
Place the jalapeños on a cookie sheet. Place sheet in preheated oven. Cook for about 10 minutes. (Skip this step if you prefer your finished jalapeños to be more raw and crunchy.)
Remove from oven and allow to cool slightly so you can handle them.
Sprinkle a small bit of the Cotija cheese into the bottom of each jalapeño.
Add a nice bit of the grilled beef.
Place 2 - 3 tomato wedges on each jalapeño.
Top with a spoonful of pico de gallo.
Place jalapeños back on cookie sheet and place back in oven.
Cook, watching closely, just long enough to warm though, about 10 - 15 minutes.
Remove from oven when hot and place on a serving dish or individual serving dishes.
Quickly, while they are still hot, grate a generous layer of Cotija cheese over all poppers.
Spoon a small amount of warm salsa over popper.
Serve warm with a couple lime wedges.