In a small bowl, combine sour cream, cilantro, minced onion, juice from half a lime (whole lime for 4 servings), a pinch of minced garlic, a pinch of cumin, and 1 tablespoon olive oil (2 tablespoons for 4 servings). Taste and add more garlic if desired. Add water 1 tsp at a time until mixture reaches a drizzling consistency. Season with salt and pepper to taste.