The ornamental design for a suctioncup handle, as shown and described.
FIG. 1 is a front top right perspective view of a suction cup handle.
FIG. 2 is a front top left perspective view thereof.
FIG. 3 is a front bottom right perspective view thereof.
FIG. 4 is a front bottom left perspective view thereof.
FIG. 5 is a right view thereof.
FIG. 6 is a left view thereof.
FIG. 7 is a front view thereof.
FIG. 8 is a back view thereof.
FIG. 9 is a top view thereof; and,
FIG. 10 is a bottom view thereof.
The broken line showing of parts of the drawings is included for the purpose of illustrating use and environment, and forms no part of the claimed design.