1. In medium bowl, combine shrimp and next 5 ingredients. Cover and chill 30 minutes.
2. Heat oil in large cast-iron skillet over medium-high heat. Add shrimp and cook 1 to 2 minutes per side or until charred and cooked through.
3. Divide guacamole evenly among corn tortillas. Place shrimp over guacamole. Top with desired toppings.