In a medium bowl, combine the crab meat, diced avocado, chopped cilantro, red onion, lime juice, salt, and pepper. Gently mix to combine.
Lightly warm the corn tortillas (this makes them pliable and less likely to break). You can do this in a dry skillet, microwave, or briefly in hot oil.
Dip each tortilla briefly into the enchilada sauce, then place about 2-3 tablespoons of the crab and avocado mixture down the center of the tortilla. Roll up and place seam-side down in a 9x13 inch baking dish.
Pour the remaining enchilada sauce over the rolled enchiladas. Sprinkle evenly with shredded Monterey Jack cheese.
Bake for 20-25 minutes, or until the sauce is bubbly and the cheese is melted and lightly golden.
Let stand for a few minutes before serving. Garnish with extra cilantro if desired.
Notes
These enchiladas are best served immediately. For a spicier kick, add some chopped jalapeño to the filling.