If using cooking spray, spray a 24-cup non-stick mini muffin pan with cooking spray. If using vegetable oil, brush both sides of each wonton wrapper with a thin layer of vegetable oil using a pastry brush.
Push each wonton wrapper into a well of the mini muffin pan.
Bake for 10-12 minutes until golden. Remove from the oven and increase the heat to 400 degrees F for the shrimp later on.
Remove the baked wonton cups to a wire rack to cool completely.
For the guacamole:
Halve the avocados and remove their pits. Scoop out the flesh and discard the skins. Roughly chop the avocado into cubes (you should have about 1 1/4 cups of cubed avocado).
Add the avocado to a wide, shallow bowl. Use a fork to mash as smooth as you like it.
Stir the lime and hot sauce into the mashed avocado.
Finely chop the cherry tomatoes and add the avocado along with the cilantro and scallion. Gently fold together until combined. Season with salt to taste (usually just a pinch).
For the shrimp:
Combine the shrimp, olive oil, garlic and Cajun seasoning in a medium bowl along with a pinch each of salt and black pepper. Stir to coat the shrimp.
Tip the contents of the bowl out onto a rimmed baking sheet. Bake for 6-7 minutes (the oven should be at 400 degrees F from earlier) until pink and cooked throughout.
Fill each baked wonton cup with a slightly heaped teaspoonful of guacamole. Top each one with a shrimp. Sprinkle with the chopped cilantro.
Serve immediately – the wontons will start to become soft very quickly once filled.
If you need to make these ahead – prep the wonton wrappers and shrimp in advance. You can keep the baked wontons in an airtight container at room temperature for up to 2 days. You can keep the cooked shrimp in an airtight container in the fridge for up to 1 day. Make the guacamole just before filling and serving otherwise it will start to oxidize, turning brown.