Cooking the shrimp: Heat the olive oil over very low heat. Add the garlic and cook for 3 to 4 minutes. Do not let the garlic burn.Add the shrimp and cook until they are pink all over. Season with salt and pepper to taste.Remove from heat and set aside.
Frying plantains: Heat the frying oil over medium heat (175 ºC [350 ºF]).Fry each slice until light golden brown (about 5 minutes). Press the slices with a lemon squeezer to form small cups.Once all the cups are formed, fry them again over medium heat until they turn golden brown.
Mashing the avocado: Peel avocado and crush using a fork until it doesn't have any lumps. Season with salt and pepper to taste. Mix in the lime juice.
Assembling: Spoon about tablespoons of avocado mix into the cups.Top each with a shrimp and garnish with cilantro leaves.Serve immediately.