1. In a 10- to 12-inch frying pan over medium-high heat, brown bacon, turning slices once or twice, about 5 minutes total. Transfer to towels to drain; discard fat in pan.
2. Spread mayonnaise on 1 side of each toast slice. Mound salad mix equally on mayonnaise on 2 slices. Lay 3 slices of bacon on each mound of salad mix and cover evenly with pickled ginger. Lay remaining toast, mayonnaise side down, on top. Cut each sandwich in half.