Lightly grease the grill grates and heat the grill. Season the sardines with salt. Carefully thread the sardines onto a skewer, making sure all the spines line up on 1 side of the skewer. Place the skewers, spine-side down on the grill. Gently turn the skewers over only once. This way, when you turn the skewers over, the spines will keep the sardines from breaking apart and falling off the skewers.
Cook for few minutes on each side and serve immediately.