In a small sauté pan, heat the oil over medium heat until shimmering. Add garlic and sauté for about 1 minute, or until lightly golden brown. Add pepper flakes and sauté for a few seconds.
Stir in hoisin sauce, peanut butter and water, and reduce the heat to medium-low so the sauce simmers gently. Add lime juice and simmer, stirring, for 3 to 4 minutes to allow the flavors to blend.
Let the sauce cool to room temperature.