Is it fairly common for student glider pilots to have wing tip strikes, especially in gusty cross wind conditions?
Most gliders have dihedral, giving more wingtip clearance than you probably are envisioning.  Many glider pilots routinely use the wing-down (slipping) method of crosswind correction.
As far as general handling while landing in gusty crosswind conditions, most tailwheel airplanes sit in a much more nose-high attitude than most gliders, and have the landing gear much further forward ahead of the CG, and therefore are much more prone to ground-looping.  And groundloops often involve wingtip contact with the ground-- on the downwind side.
On the whole the crosswind limits below which a safe landing without damage to the aircraft can reasonably be expected, are likely higher for most gliders than for most tailwheel light airplanes.
As for the part of your question contained in the actual title-- no, it is not common for student glider pilots to strike the wingtip into the ground before the main wheel touches.