ok, here are the 2 most logical choices:
1. if you hold the kryptonite far enough away, you can weaken her, but not hurt her, since kryptonite is a range affecting weakness.
2. she could willingly be bondaged, with titanium, would be a little difficult to get out, not much, but if she tuly wanted the tickling, she'd stay put.
and may i suggest tickling her bare soles with a feather, i love to see the woman of steel brought to her knees by a small feather, it's a cool irony, or something like that.