Heat the oil in a deep saucepan over medium heat. Add the garlic and cook until fragrant and pale golden brown, 1 to 2 minutes. Do not let brown too much, or the garlic will become bitter.
Stir in the sour orange juice, water, cumin, oregano, 1 teaspoon salt, and 1 teaspoon pepper. Stand back; the sauce may sputter. Bring the sauce to a rolling boil. Taste for seasoning, adding salt and pepper. Let cool to room temperature, then stir in the cilantro. Transfer the mojo to a jar or bottle with a tight-fitting lid. Serve in the jar and shake well before serving.