Questions & Answers about Við dáumst að útsýninu frá fjallinu.
Because the dictionary form is dást að, not dá að. This is a middle-voice verb, and the -st is part of the verb itself in this meaning.
So við dáumst means we admire / we marvel at.
For learners, it is best to remember the whole pattern as dást að + dative.
No. Icelandic að can be more than one thing.
Here, að is a preposition, not the infinitive marker. It is required by the verb dást. With this verb, að introduces the thing being admired, and that noun goes into the dative case.
So in this sentence, að útsýninu is not to view or anything like that. It is the prepositional phrase that goes with dáumst.