DNAT (port mapping) for OpenVPN:

/ip firewall nat add chain=dstnat action=dst-nat to-address=192.168.0.254 to-ports=1194 protocol=udp dst-port=1194

For SSH (forward to non-standard port):

/ip firewall nat add chain=dstnat action=dst-nat to-address=192.168.0.254 to-ports=22 protocol=tcp dst port=2222