Is wiping one's hand with a tissue and throwing it in the outdoor area of the mosque considered an act of disbelief (kufr), given that there was no intention of disrespecting the mosque and the person was ignorant of the ruling on such an act?

It is highly unlikely that the action mentioned in the question occurred as a form of mockery or insult to the mosque. Rather, the questioner affirmed that he did not intend such, therefore it has no relation to disbelief (kufr). The legal ruling for this action is dislikeness (karahah) due to its incompatibility with perfect cleanliness, as purifying the mosque and maintaining the cleanliness of its premises is an important matter. It appears that the questioner is suffering from obsessive thoughts in this regard, and he should discard these ideas.