Activate Selvala by tapping it, causing each player to reveal the top card of their library, then causing you to add ({G} magic symbol) and gain 1 life for each nonland card revealed this way, then causing each player to draw a card.
Tolarian Kraken triggers, causing you to pay ({1} magic symbol) to untap Selvala.
Repeat.
NOTE: If everyone would happen to reveal a land, Selvala makes no mana, and therefore you will need to supplement mana to pay for Tolarian Kraken's trigger if you have no mana in your mana pool.