If the anger disappears once it has been seen, what is that state of mind then? After that, saw mind has two sides, no klesa and klesa, like a coin.
The state of mind according to your question is doubt or confusion. It is Kilesa(ignorance). Otherwise it is simply the awareness that anger has disappeared.
According to the Visuddhimagga (Path of Purification), vipassana (insight meditation, mindfulness meditation, also wisdom or psychological insight) is characterized by upacara-samadhi (neighbourhood samadhi or access collectedness). Anger is one of the five nivarana (hindrances to upacara-samadhi) called uddhacca-kukkucca (restlessness and scruples, where anger is a form of restlessness). While upacara-samadhi provides access to appana-samadhi (full samadhi, jhana), it also provides access to panna (wisdom, insight, knowledge relevant to nibbana or nirvana), whereas appana-samadhi does not provide access to panna. A person does not practice vipassana merely by sitting on a meditation cushion and focusing the mind. The practice of vipassana also requires a state of upacara-samadhi. Hence, an angry person cannot practice vipassana. He must first calm his anger. After calming his anger, he may not be able to enter upacara-samadhi because of the presence of another nivarana. The term “klesa” is a Sanskrit variation of the Pali term kilesa (defilement, the Visuddhimagga lists ten defilements). Once a state of upacara-samadhi is achieved, panna may or may not arise. When panna does arise, it can take many forms, some of which are symbolic. To perceive the mind as having “two sides” was a symbolic representation of the fact that a sankhara (karma-formation, the psychological causes of an action) can be kusala (wholesome, free of defilements) or akusala (unwholesome, defiled) but not both. The mind, of course, has a vast number of sankhara(s), none of which are both wholesome and unwholesome. It would be a serious mistake to view the mind as having two sides like a coin, because (1) is a mere metaphor and (2) it is seriously ignorant of the Buddhist teachings.