How do you freeze blueberries so that there are ice crystals inside?
Normally freezing processes try to avoid forming large ice crystals by freezing rapidly and maintaining a temperature well below the freezing point of the liquid in the product (not simply 0&deg;C due to sugar and other solutes, which concentrate as some liquid freezes).

I suspect that the ones you are aiming to imitate have been through a thermal cycle in transit -- quite possibly as you take them home. 

So you can try to do the opposite. Freeze fresh blueberries at home, in a single layer but fairly slowly (perhaps freezing them in an isulated container and/or adding large containers of room temperature water to the freezer at the same time). Allow to nearly defrost and freeze again. If you're starting from frozen berries, allow them to nearly defrost and then refreeze slowly.

You'll have to be careful about the quality of other things in your freezer doing this, and the goal is to stay cold enough that food safety isn't an issue, or at least no more of an issue than keeping fresh berries in the fridge for a few days before freezing. As a result I leave the mechanics at an exercise for you. A cool box with a thermometer inside may be useful.