This lesson plan has great incorporation of face to face instructional strategies and technology integration. By having students read and discuss the primary source in and out of the classroom allows for a deeper understanding of the information. It also allows students of various skill levels to think and reflect on material and then are given the chance to respond.
The use of inductive and deductive reasoning is a good way to build students knowledge about Human rights. Possibly adding more historical background and/or other examples of genocide might be helpful for students to understand why the Cambodian genocide was a specific violation of the UN's Declaration of Human Rights. Also giving a full background to why the UN declared these Human Rights might help students to contextualize the material. Also providing the Declaration of Human Rights in Plain Language (which makes it easier for students to understand) might be helpful for students of different reading levels to comprehend the declaration easier.
Also adding images will help visual learners to understand what genocide really looks like.
Assistive technologies are missing from the lesson plan, including text to voice capabilities. I think a lesson or previous use of wiki's is a must prior to using this lesson. That way students will understand the technology they are using to discuss the topic. You may also want to model how to write proper discussions on your wiki page before letting students just begin. This way, students can use the model discussion while writing their own.
Overall, I think using the Face to Face strategies along with technology (wikis) to continue the discussion is great for students. Well done.