Whisk together mayonnaise, lime juice and curry powder in a small bowl; set aside. Preheat grill to medium-high. Grill sausages, turning, until cooked through, about 25 minutes, or when an instant-read thermometer inserted in center registers 170F. Slice sausages in half lengthwise.
Toast tortillas on grill until slightly puffed, about 30 seconds.
Transfer to a work surface.
Spread 2 Tbsp. mayonnaise mixture onto each tortilla. Divide spinach among tortillas, arranging it across middle. Top with two sausage halves and some mango slices.