Preheat oven to 400 degrees.
Fit a large, rimmed sheet pan with parchment.
Place the cream cheese, cheddar, onion, tomatoes, cilantro, chili powder, cumin, hot paprika, paprika, salt, and pepper in a mini food processor, and process until smooth. (You can also mix it by hand in a large bowl, or in a standing mixer with a paddle attachment.)
Divide mixture between halved jalapenos.
Top with panko, and drizzle with melted butter.
Bake for 20 minutes, or until hot and bubbly.
Turn the broiler on and bake the poppers until the panko is golden brown, approximately 2 minutes.
Serve hot, or at room temperature.
To store: Keep in an airtight container in the refrigerator for up to 3 days. To reheat: bake in a 350 degree oven until hot, about 15minutes.