For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:jason-kurzik/openSUSE_Tumbleweed/home:jason-kurzik.repo
zypper refresh
zypper install zerotier-one
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:jason-kurzik/15.5/home:jason-kurzik.repo
zypper refresh
zypper install zerotier-one
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:jason-kurzik/15.4/home:jason-kurzik.repo
zypper refresh
zypper install zerotier-one