These are Unicode characters that are not supported by the font used by dnSpy.
Usually, you'll see it when the code is obfuscated or in cases where the developer used languages as Chinese and Russian in their code. But yeah, usually obfuscation.
You can try to deobfuscate this .Net binary by using de4dot which is doing an incredible job with deobfuscating obfuscated .net applications. de4dot's engine was later used to create dnSpy which is my favorite .Net decompiler.
The separating dots are the dot Operator, just as in most popular programming languages, the dot operator is used to access members of variables, types, etc. "Members" can be a method, attribute, and others.
In your case,
\u0001 is a method of
\u0002 which is a member of the variable