1Toss cabbage, half the cilantro, juice of one lime, jalapeño, and a pinch of salt in a bowl. Set aside to soften slightly.
2Stir sour cream with 1 tbsp lime juice, minced garlic, and salt to taste. Set crema aside.
3Season shrimp with salt, pepper, cumin, and cayenne. Heat oil in a skillet over medium-high. Sear shrimp 2–3 minutes per side until pink and cooked through. Remove to a plate.
4Warm tortillas in the skillet or directly over a gas flame until pliable, about 30 seconds per side.
5Build each taco: crema, shrimp, slaw, onion, cotija, remaining cilantro. Serve with lime wedges.