Heat butter in a small skillet over medium high heat. Add garlic and shrimp, sprinkle with chili powder and cayenne while directly in the pan. Saute for a few minutes on each side until shrimp are no longer clear and have a nice golden color on outside.
Cut avocados in half; slice lines through the avocado vertically and horizontally then scoop the flesh out with a spoon. Peel and dice cucumber. Chop the spinach or baby kale into bite sized pieces. Combine in a bowl with the shrimp.
Puree all the dressing ingredients together in a food processor until it is smooth. Taste to your preferences. Pour dressing over the salad and serve immediately (or store individual parts separately in the refrigerator until you're ready to serve). Top with fresh cilantro and peanuts.