In a mixing bowl, hand mix ground beef with diced jalapenos, cumin, salt and pepper. Form 4 patties and refrigerate 30 minutes.
In a clean small bowl mix cream cheese and cheddar jack with a spoon. Form 4 balls about the size of a ping-pong ball. Flatten into disks and refrigerate.
Pan sear or grill burgers 4-5 minutes on one side, flip, top each burger with a cheese disc and cook an additional 4-5 minutes (or until the burger’s center reaches 160°F using an instant-read thermometer).
Mix fried jalapenos and fried onions. Place each burger on a bun’s bottom half, top with fried jalapeno-onion mixture and bun’s top half.