Yes, you get 4 tokens. The instructions of a resolving spell/ability are followed in the order they are written. So Sarkhan's Rage first deals 5 damage to the targeted creature/player, and then deals 2 damage to you, which results in two triggers from the Commando, each will give you 2 tokens when it resolves.
If Sarkhan's Rage had used "deals ... damage" only once, the damage would have been dealt simultaneously, and Blaze Commando's ability would have triggered only once (compare Sarkhan's Rage with Char). In general, as is the case here, each action verb refers to one simultaneous action (under C.R. 608.2c, you "apply the rules of English to the text" of a spell when carrying out its instructions).
Former Rules Advisor
"Everything's better with pirates." - Lodge
(The Gamers: Dorkness Rising)
"Any sufficiently analyzed magic is indistinguishable from science."
(Girl Genius - Fairy Tale Theater Break - Cinderella, end of volume 8)
EDIT (Aug. 5, 2017): Added second sentence.