Yes, Noumenon is our Tathagata nature, our Buddha Nature, Tao, God, Allah, Brahmin... whatever that thing is that is beyond the dualism of existence and non-existence: the Mind.
Noumenon is the opposite of phenomena, things that are perceivable through the senses or in Buddhist terms are a part of the five skandhas (see Surangama Sutra).
This is why it is so important to become more detached from phenomena because they detract the Buddhist from realizing the only worthy goal of the Noumenon, the Source of all things, the Us that is beyond time and space.
The more one develops a worldly way, the more one is attached to meaning-ful phenomena be it money, sensual pleasure, relationships, and the infinite dualities that trap us to the wheel.
The more one grows in the spiritual path, the more one is able to perceive the foundational unity of all things. The profound truth in Emptiness.
One is unable to be so attached to any particular thing--not with a numbness, but with a crystal clear clarity developed through the understanding of Dharma and most importantly through the transformation of consciousness itself that takes place by success in meditation/awareness/vipassana.
This is the Right Path as espoused by the Eightfold Path and the last question you asked is different question, that would take an entire paper to discuss, but basically yes.