Preheat oven to 500 degrees. Line a baking sheet with aluminum foil. Hold 4 raw tomatillos back, but place the rest of the halved tomatillos and the roma tomato cut-side down on the baking sheet. Bake until they begin to toast, about 20 minutes.
In a food processor, combine the roasted tomatillos and tomatoes, the raw tomatillos, jalapeños, red onion, garlic, cilantro, cumin, and oregano. Pulse until the mixture is mostly smooth with some texture
Taste and add more chiles and/or seeds depending on your preference for spiciness.
Add lemon and lime juices, and season to taste with salt and pepper.
Notes
Remember, the salsa tastes spicier when warm and when tasted without food. It will be milder after chilling and when eaten with food.
If you're a little shy about spice, add a little bit at a time and taste as you go along.
Don't over-blend your tomatillos! Keep a little texture in the sauce.
You can make ahead your salsa, and it can be stored easily in the fridge. Also, you can freeze it for up to three months.