Instructions
1Start the rice first so it is hands-off for the rest of the cook: combine the rinsed rice, water, and salt in a saucepan, bring to a boil, then cover and drop to the lowest heat for 15 minutes. Do not lift the lid and do not stir it. After 15 minutes pull the pot off the heat and leave it covered another 10 minutes — that rest is what evens out the wet bottom and the firm top. It holds fine, covered, until you plate.
2While the rice cooks, make the crema: put the avocado, sour cream, lime juice, cilantro, the pinch of fajita spice, and the salt in a blender or small food processor and run it smooth, adding water a tablespoon at a time until it pours in a thick drizzle. Scrape it into a bowl and refrigerate until dinner.
3If your shrimp came tail-on, pull the tails now, before seasoning — pinch the fin and slide the shrimp out. It takes about 5 minutes for 1.5 lbs and it is much worse to do at the table with a toddler. Then pat the shrimp very dry with paper towels and toss them in a bowl with 1 tbsp of the oil, the chili powder, cumin, smoked paprika, garlic powder, and salt. Dry shrimp is what lets them brown instead of steam.
4Heat the remaining 1 tbsp oil in your largest skillet — 12 inch, cast iron if you have it — over medium-high until it shimmers. Add the onion and peppers. If they do not sit in something close to a single layer, split them into two batches and give each 5-6 minutes; all of it at once will steam instead of char and you will get soft, gray strips. Stir only every minute or so, and pull them when you see real black edges. Move them to a plate.
5Return the skillet to medium-high and lay the shrimp in a single layer — in two batches if they do not all fit without touching. Cook 2 to 2½ minutes per side for jumbo shrimp (90 seconds per side if you got large), until just pink and opaque through. Shrimp go rubbery fast, so pull them the moment the last gray disappears.
6With the shrimp out and the skillet still hot and empty, squeeze half a lime into the pan and scrape hard for about 15 seconds. Everything the spices left on the bottom lifts into a few tablespoons of dark pan juice — pour that straight over the shrimp. It costs nothing and it is the single biggest flavor step in the dish.
7Return the peppers and onions to the skillet and toss for 30 seconds to bring everything back to temperature.
8Finish the rice: fluff it with a fork, then fold in the lime juice, the chopped cilantro, and the zest of one lime — grate the zest off before you juice it, because the zest is where the lime smell actually lives and the juice alone reads as sour rather than limey. Warm the tortillas in a dry skillet about 20 seconds per side, or wrapped in a damp towel in the microwave for 45 seconds.
9Serve the shrimp and peppers with the warm tortillas, the cilantro-lime rice, the avocado crema for drizzling, and lime wedges at the table.