In a small metal bowl combine lime juice, cumin, mayonnaise, cilantro, and salt and pepper to taste. Set aside.
Heat a medium saute pan to medium high. Saute the peppers and onions in 2 tbsp canola oil until soft and lightly browned.
Heat a second saute pan over high heat. Sprinkle shrimp with taco seasoning. Toss to coat. Place 2 tbsp oil in the hot pan and saute shrimp in oil for 3-5 minutes, until shrimp are cooked through.
Distribute shrimp and pepper/onion mixture evenly amongst 8 warm tortillas. Top with diced avocado. Lightly spoon cilantro cream over taco, sprinkle with cheese and serve.
If you prefer, you can substitute corn tortillas for the flour tortillas. For a lower fat version, use pan spray instead of oil, and low fat sour cream and mayonnaise.