If you make up a REAL salty solution, and don't let them dry before you roast them, it sort of makes a "crust".
Here is what I do (method discovered by laziness)...
I usually have the seeds in a colander and they don't really ever dry out, so while they are wet I mix in spices....today it was salt, paprika, and some garlic powder.
The seeds being wet, the spices sort of coat them.
Then I toss them in a pan with melted butter and stir the whole thing up to coat everything.
Then in the oven for a while.......stirring them every five minutes or so.
The moisture comes out pretty quick, and when thye are dry and crispy, I am done.
Then I eat them.