The ornamental design for a can openingtab, as shown and described.
1. Can opening tab
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Top
1.5 : Bottom
1.6 : Left
1.7 : Right
1.8 : Opening tab mounted on the can end
The ornamental design for a can opening tab as shown; legends/description: reproductions 1.1: perspective view (front, top and right), 1.2: front view, 1.3: back view, 1.4: top view, 1.5: bottom view, 1.6: left side of the opening tab, 1.7: right side of the opening tab, 1.8: opening tab mounted on the can end; in the drawings, the broken lines showing portions of a can lid depict environment and form no part of the design.