Thank you. Your translation of "Как вы на это смотрите" makes sense and feels natural. However, the given translation "how did you see that" doesn't seem to match. Would "как вы видил ето" work for that?
"Он предложил это. Как вы на это смотрели?" could be literally translated as "He proposed that. How did you see (or look at) that?", but the correct translation would be "He proposed that. What did you think about that?".
Source: am a native speaker.