Preheat the oven to 400°F (200°C). Place the slices of bread on a baking sheet.
In a mixing bowl, combine the minced garlic with 2 tablespoons of olive oil. Brush this garlic oil mixture generously over each slice of bread.
Bake the bread in the preheated oven for about 8-10 minutes, or until it is golden brown and crispy.
While the bread is baking, heat a skillet over medium heat. Add the shrimp, seasoning them with salt, pepper, and red pepper flakes if using.
Cook the shrimp for about 2-3 minutes on each side, or until they turn pink and opaque. Remove from heat and squeeze lime juice over the shrimp.
Peel and mash the avocado in a bowl, adding a pinch of salt and a drizzle of olive oil to taste.
Once the bread is done, remove it from the oven. Spread a generous amount of mashed avocado on each slice.
Top the avocado spread with the sautéed shrimp. Garnish with fresh cilantro or parsley if desired.