Heat olive oil in large skillet over medium low heat. Cook the garlic slices until tender but not brown. Transfer with slotted spoon to paper towels and reserve.
Turn the heat under the skillet to high. Toss the shrimp with the salt and pepper. When the oil is nearly smoking, add the shrimp. Saute, stirring and shaking the pan to prevent sticking, 3 to 4 minutes or just until shrimp are slightly under cooked. Remove from the heat. With a slotted spoon, transfer the shrimp to a platter, leaving as much liquid as possible in the skillet.
Return skillet to burner, and reduce heat to medium. Add the garlic slices and the anchos, and saute, stirring frequently, until the oil begins to turn orange from the chiles. Stir in fish stock/clam juice, along with the shrimp and any juice that has collected on the platter. Add the lime juice and parsley, bring to a boil, and remove from heat.