Sauce: Pulse all the sauce ingredients in a food processor or blender until mostly smooth.
Slaw: Toss a portion of the sauce with the shredded cabbage so it is lightly dressed. The rest of the sauce will be used to drizzle on top of the tacos. You will most likely have extra sauce, but it's great served with raw or cooked veggies.
Shrimp: Pat the shrimp dry with paper towels. Toss the shrimp in a small bowl with the spice mix to coated thoroughly. Heat olive oil a large skillet over medium high heat. Add the shrimp to the hot pan and saute for 5-8 minutes, flipping occasionally, until the shrimp are cooked through.
While shrimp are cooking, smash the avocados on a plate using a fork.
Warm each tortilla in a separate dry heavy skillet about 90 seconds per side. Stack on a plate and cover to keep warm as you finish the rest of the tortillas.
Assembly: Spread warm tortillas with smashed avocado, add slaw, then shrimp. Finish with Cotjia cheese, sliced jalapenos (if using), and drizzle with extra sauce. Serve with lime wedges.