This article explains how to list VM's cpu/memory usage using PowerCLI.
Those metrics are available as below.
ExtensionData.Summary.QuickStats.OverallCpuUsage
ExtensionData.Summary.QuickStats.HostMemoryUsage
Here is an example PowerCLI command to list this.
Get-VM | Select Name, NumCpu, MemoryGB, @{N="CpuUsageMHz"; E={$_.ExtensionData.Summary.QuickStats.OverallCpuUsage}}, @{N="MemoryUsageMB"; E={$_.ExtensionData.Summary.QuickStats.HostMemoryUsage}}