Wash and dry all produce. Drain pineapple, reserving juice in a large bowl. Zest and quarter lime (quarter both limes for 4 servings). To bowl with pineapple juice, whisk in a drizzle of oil, juice from 1 lime wedge (2 wedges for 4), half the lime zest, half the Southwest Spice (you’ll use the rest later), and a couple large pinches of salt and pepper.

Add steak to bowl with marinade and turn to coat. Marinate at least 15 minutes, turning steak periodically.

Halve, peel, and thinly slice onion. Core, deseed, and thinly slice poblano. In a small bowl, combine sour cream, a squeeze of lime juice, and remaining lime zest (to taste). Season with salt. Add water, 1 tsp at a time, until mixture reaches a drizzling consistency.

Heat a drizzle of oil in a large pan over medium-high heat. Add pineapple and cook, stirring occasionally, until beginning to char, 3-5 minutes. Turn off heat; transfer to a cutting board and roughly chop. Wipe out pan.

Remove steak from marinade; discard marinade. Pat meat dry with paper towels, then season all over with salt and pepper. Heat a drizzle of oil in pan used for pineapple over medium-high heat. Add steak and cook to desired doneness, 3-5 minutes per side. Turn off heat and transfer to a cutting board to rest. Wipe out pan, then heat a large drizzle of oil in it over medium-high heat. Add onion, poblano, and remaining Southwest Spice. Cook, stirring, until softened, 5-7 minutes.

Meanwhile, wrap tortillas in damp paper towels and microwave until warm and pliable, about 30 seconds. Slice steak against the grain into very thin strips. Divide among warm tortillas and top with veggies, pineapple, and crema. Serve with remaining lime wedges on the side.