How would I do this?

[drowsy wedge]

Get the eye location with LivingEntity#getEyeLocation. You can then ray trace entities from that position in the direction the player is looking with the maximum hit distance as the maximum ray distance.

[hallow citrus]

The ray trace result ends up being the player themeselves in this case?

[drowsy wedge]

https://hub.spigotmc.org/javadocs/bukkit/org/bukkit/World.html#rayTraceEntities(org.bukkit.Location,org.bukkit.util.Vector,double,java.util.function.Predicate) you can pass in a predicate to filter out certain entities (which in your case would be the current player)