Preparation Cut skin from mango and cut flesh into julienne strips. Pick over crab meat to remove any bits of cartilage and shell and in a bowl stir together with lime juice, brown sugar, and salt to taste. If using wasabi powder, in a small bowl stir together with 2 teaspoons water and let stand, covered, 10 minutes to make wasabi paste. Cut nori sheets in half lengthwise. On a work surface put a sushi mat (see above note) with bamboo strips of mat parallel to front of work surface. (Alternatively, use a 9-inch square of heavy-duty foil as a mat.) Put 1 nori piece on mat with a short side lined up with edge of mat that is closest to you. Spread 1/4 teaspoon wasabi paste across bottom edge of nori and top with 5 or 6 mint leaves so that some stick out on each side. Top mint leaves evenly with a heaping tablespoon crab mixture and 2 or 3 mango strips. Beginning with a short side and using mat as a guide, roll up nori tightly (use mat to help tighten roll). Seal seam with a little water and with a sharp knife cut roll crosswise into 3 pieces. Make more rolls in same manner. Nori rolls may be made 3 hours ahead and chilled, covered.
Preparation Cut skin from mango and cut flesh into julienne strips. Pick over crab meat to remove any bits of cartilage and shell and in a bowl stir together with lime juice, brown sugar, and salt to taste. If using wasabi powder, in a small bowl stir together with 2 teaspoons water and let stand, covered, 10 minutes to make wasabi paste. Cut nori sheets in half lengthwise. On a work surface put a sushi mat (see above note) with bamboo strips of mat parallel to front of work surface. (Alternatively, use a 9-inch square of heavy-duty foil as a mat.) Put 1 nori piece on mat with a short side lined up with edge of mat that is closest to you. Spread 1/4 teaspoon wasabi paste across bottom edge of nori and top with 5 or 6 mint leaves so that some stick out on each side. Top mint leaves evenly with a heaping tablespoon crab mixture and 2 or 3 mango strips. Beginning with a short side and using mat as a guide, roll up nori tightly (use mat to help tighten roll). Seal seam with a little water and with a sharp knife cut roll crosswise into 3 pieces. Make more rolls in same manner. Nori rolls may be made 3 hours ahead and chilled, covered.