Place butter, flour, sugar, and salt in a food processor and pulse about 5-6 times until it has a coarse structure and large butter pieces are still visible. Add 1 tbsp water and pulse one time. Add the second tbsp and pulse again 2 times. Divide crumbs equally and transfer them to a 12 cup muffin pan. Press pie crumbs evenly with your fingers into the cups. Freeze until the oven is preheated for about 10 minutes.
Preheat oven to 350°F / 175°C.
Chop caramels roughly. I didn't chop the peanuts because I love to have bigger pieces, but you can chop them if desired. Remove muffin pan from freezer and fill caramels and peanuts into the pie cups evenly. Bake for about 20 minutes until pie crust is baked through. Remove from oven and set aside.
Melt chocolate in microwave until completely melted for about 2 minutes. Stir every 20 seconds to help avoid seizing. Stir in 1 tbsp peanut butter until just combined.
Place 1/2 tbsp peanut butter on top of every pie cup. Cover with chocolate and let cool to room temperature. Sprinkle with chopped Snickers chunks if desired. Store in an airtight container at room temperature for up to 3 days.