I looked in the json files and did a /give command using
/give popcorn_modstone_pickaxe 1 0 {CanDestroy:popcornblock["popcorn_mod:popcornblock"]}
and it worked! It also answered my other question "Getting Mod ID's"
pick command: /give stone_pickaxe 1 0 {CanDestroy:["popcorn_mod:popcornblock"]}