1 lime, cut into 4 wedges
Combine the beer and pepper flakes in a glass bowl. Stir in the shrimp. Cover and refrigerate for at least 1 hour or for up to 3 hours.
To make the sauce, combine the coffee and chilies in a small bowl. Let soak until the chilies are soft, about 20 minutes.
Heat the oil in a medium sauté pan over medium heat. Add the onion and cook, stirring occasionally, until translucent, about 5 minutes. Add the garlic and cook for about 30 seconds. Set aside.
In a food processor, pulse the almonds until coarsely ground. Add the raisins and process with 2 or 3 pulses. Add the chilies and their liquid, the onion mixture, and the remaining ingredients, except the chocolate and salt. Process until semi-smooth.
Return the sauce to the pan. Partially cover and simmer over medium-low heat, stirring occasionally, for 25 minutes. Add the chocolate; cook, stirring occasionally to blend and to keep the mixture from scorching, for about 10 minutes. Add salt to taste. (If too thick, thin the mole with coffee, water, chicken broth, or cream.)
Grill the shrimp on an outdoor grill or stovetop grill pan over medium-high heat. Cook until evenly pink, about 2 minutes on each side.
To serve, place 6 shrimp on each plate and sprinkle with fresh herbs. Accompany with a wedge of lime to squeeze on the shrimp and a small bowl of warm mole.