In a small bowl, combine the mayonnaise, relish, and chili powder. Refrigerate until ready to use. You can make this a few hours before the crab cakes.
Crab Cakes
Drain crab meat, if needed, and set aside.
In a medium bowl, add egg, mayonnaise, red pepper flakes, green onions, tarragon, and lemon juice. Mix until well combined.
Add the crab meat to the egg mixture.
Use a zip-top bag and rolling pin to crush the crackers. Then, add the crushed crackers and crab meat to the mixture. Mix until combined being careful not to break apart all the crab.
Form 8 small, equal crab cakes. Melt butter in a skillet over medium-high heat.
Add the crab cakes to the skillet and cook for approximately 5 minutes per side or until a light golden brown.
Remove from the heat and serve immediately.
Notes
Optional: use finely chopped pickles in place of the relish