Building on critical, performative, and emancipatory visions for digital citizenship education, this paper analyzes social media within systems of global capitalism in a time of climate crisis, which not only introduce opaquely complex agencies but shape relations on a planetary scale. To reconceptualize digital citizenship education in a computational age, with consideration for just relations and the future health of the planet, this paper draws on the work of African philosopher Achille Mbembe, who articulates how plasticity among human and non-human agencies is being used within capitalist systems to take power over the living -- a power that is shaped by colonial hierarchies. In place of individualism, Mbembe's philosophy emphasizes the need for collective action to repair harms and work across differences towards protection and sharing of what we have in-common. Connecting his thinking to digital citizenship, there is potential for education to support decolonial disenclosure of social media's capitalist capture and engage in deep historical learning towards the replacement of exclusionary, necropolitical forces with care and communing in support of life. This paper offers possibilities and provocations for digital citizenship education, inviting readers to respond in their own contexts in ways that consider our planetary relations.