I've had a Himalayan salt block (8x8x2 inches) for a month or so, and used it a few times, but nothing really grabbed me until today.
I had a couple of small salmon filets to cook on the block. I always do them skin side down (we love the skin), and only the skin picks up a tiny bit of salt from the block.
Today's filets were just enough to cover half the salt block, and I wondered how I could use the other half, so I grabbed a big red onion and cut two slices, each about 3/4 inch thick, and put them on the other half of the block. Cooked salmon and onion for about 20 minutes at 300 degrees.
MAN!!! Those onion slices picked up so much salt from the block that they were just out of this world! So delicious I was wishing I had another onion in the house to make some more.
I guess the key is that for a food to pick up salt from the block, it needs a high water content, and fresh onion certainly qualifies.