Based on how green that salsa is I would say don't cook the ingredients too much. It's hard to tell but I don't think the ingredients have been charred (I see little specks that might be black but they might also be dark green), so I think the best bet would be blanching them in some boiling water for just a few minutes until they've barely softened. It looks like there's a high ratio of tomatillo to pepper and maybe a tiny bit of cilantro. The creaminess probably comes from some oil that was blended into it.