You won't have a separate ticket number. All flights should be booked on the same ticket number. What you will have is a different PNR for ANA.

You should be able to retrieve the ANA PNR from UA - either the website or from a res agent. On the website, you can open your reservation, you should see a line near the top saying the reservation contains partner flights, with a link to view the additional PNRs. Or, if you call UA reservations, an agent should be able to provide it.

You don't even need the PNR to see the reservation on the ANA site. You should be able to open it on ANAs site with the ticket number (the same - starts with 016) and name.