In a bowl, combine the first 11 ingredients. Gently mix in the crab meat being careful not to break up the pieces of crab. Using a ⅓ cup measure, form mixture into 8 crab cakes. Place on a baking sheet and refrigerate for at least 30 minutes.
Heat a large sauté pan to medium high. Add the butter and olive oil to the pan. When the butter begins to foam, add the crab cakes and fry for about 3 - 4 minutes per side or until golden brown. Remove from pan to a serving platter. You may need to fry the crab cakes in 2 batches depending on the size of your pan. Add more butter and olive oil as needed.
To make the spicy aioli, combine the mayonnaise, yogurt and chipotle powder in a small bowl.
Serve crab cakes on a bed of mixed greens with the spicy aioli.