POS for .NET is probably the way to go.
Most receipt printer manufacturers will provide an OPOS service object.
And as this MSDN article states, POS for .NET is compatible with OPOS v1.8 service objects.
OPOS / UPOS (on which POS for .NET is based) is IMHO a poorly-designed API (designed by device manufacturers rather than application developers), but it's the best you have today.
I don't have any specific samples but the basics are the same as OPOS - you need to Open, Claim, Enable a device, then you can call its methods (such as Print). You might try looking at an OPOS sample, for example this PosPrinter1 sample, which will probably be very similar to POS for .NET.
This blog has some information about setting up POS for .NET that might be helpful.
UPDATE
Here's a VB Hello World for an OPOS printer. You first need to create a printer and add it to the registry with the required Logical Device Name = LDN. I believe the Epson ADK includes a utility to add a printer in the registry. This utility can also perform a health check on the printer to check it is installed correctly. Once you've done this, it should be easy enough to adapt the code below to POS for .NET
OPOSPOSPrinter.Open "MyPrinter" ' LDN of your printer
OPOSPOSPrinter.Claim 500 ' Timeout
OPOSPOSPrinter.DeviceEnabled = True
'- Print
OPOSPOSPrinter.PrintNormal 2, "Hello world"
'- Close the printer
If OPOSPOSPrinter.Claimed then
OPOSPOSPrinter.Release
End If
OPOSPOSPrinter.Close