I would recommend Sikaflex Marine, available in Bunnings and in Supecheap for about $18. I´ve used it successfully for footpad edges coming off. I believe you can find them in grey and white colour.
This is a polyurethane based adhesive formulated for marine environments i.e. aggressive UV radiation, temperature fluctuations and indeed salt-water. It also has great gap-filling capabilities, which comes handy when you try to glue the foamy EVA pad material with the board skin.
I would not recommend Superglue for 2 reasons: a) Unless is a special grade, cyanoacrylate glues (supeglues) have low resistance to moisture and heat, they hydrolyse easily, and b) It only works with a thin layer interface, i.e. when you try to fill the gap existing between the rough skin and the foamy pad, it does not cure adequately.