To make the spice blend: Mix together the paprika, sumac, parsley, and jalapeno powder.
To make the meatballs: Position 1 oven rack 6 inches from the broiler and 1 in the center of the oven. Preheat the oven to 400°.
Coat a large oven-safe skillet with 2 tablespoons oil, and set over medium-high heat. Add the onion, 1 teaspoon spice blend, and 1/2 teaspoon salt. Cook, stirring occasionally, until onion is just translucent but still has a little bite, about 5 minutes. Transfer to a large bowl, and let cool completely; reserve skillet.
Add the meat, tahini, panko, egg, remaining spice blend, 1 tablespoon oil, and 2 teaspoons salt to the bowl with onions. Mix with your hands until evenly blended.
Coat skillet with oil. Form the meat mixture into twelve 2-inch balls. Put them in the skillet in a single layer; scatter the tomatoes all around.
Roast for 20 minutes on the center rack. Set the broiler heat to high, and move the skillet to the upper rack. Broil meatballs until browned and an instant-read thermometer inserted into the center registers 160°, 2 to 8 minutes more. Serve hot with the tomatoes.
Recipes reprinted from Mastering Spice, by Lior Lev Sercarz. Copyright 2019. Published by Clarkson Potter, an imprint of Penguin Random House, LLC.