SELECT * FROM tblCustomers INNER JOIN tblResellerSuppliers ON tblCustomers.CustomerID = tblResellerSuppliers.AllocatedSupplierID
WHERE ResellerID = @ResellerID ORDER BY Name

How would i execute this query using the generated code?

Please check the example provided in the manual under the title Multi-entity filters in the following path: "Using the generated code -> Adapter/SelfServicing -> Filtering and sorting -> Advanced filter usage"

Also in the docs check the example at How do I filter on fields in another entity? in the following path: "Best practises -> How do I ... ?"