Season the thighs with chili powder, cumin and salt. Sear them in the oil in a wide lidded pan, 3 minutes a side, until browned but not cooked through. Set aside.
In the same fat, toast the dry rice with the onion over medium heat until the rice turns nutty and opaque, 5 to 6 minutes. This toast is the dish.
Stir in the garlic for 30 seconds, then the tomato sauce, scraping up the browned bits from the sear.
Add the broth, stir once, and nestle the thighs on top with any juices.
Cover, drop to low, and simmer 20 minutes without lifting the lid.
Scatter the peas over, lid back on, heat off, and rest 10 minutes. The rest finishes both the rice and the chicken.
Fluff around the chicken, finish with cilantro, and serve with lime wedges.