Arrange racks in the middle and upper third of the oven; preheat the broiler. Line 2 baking sheets with foil. Toss the bell peppers and onion with the olive oil and a big pinch of salt and pepper on one of the baking sheets. Broil on the middle oven rack, stirring occasionally, until the vegetables are crisp-tender and lightly charred, 15 to 20 minutes.
Meanwhile, tear the tortilla into small pieces and combine in a large bowl with 1/4 cup hot water. Stir well and set aside to soften, about 5 minutes.
Combine the rice, salsa, 2 cups water and a pinch of salt in a medium saucepan. Bring to a simmer, stir well and cover. Reduce the heat to low and cook until the rice is tender but still saucy, about 15 minutes. Uncover and stir well.
Brush the second baking sheet with olive oil. Using your fingers, squish and crumble the soaked tortilla pieces in the bowl. Add the beef, egg, chili powder, cumin, 3/4 teaspoon salt and a few grinds of pepper; mix well. Form into 16 meatballs, about 2 tablespoons each. Place on the oiled pan. Broil on the upper oven rack until browned and cooked through, 8 to 10 minutes.
Divide the rice among plates. Top with the meatballs, peppers and onion. Serve with sour cream, jalapeños and cheese.