The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
Definitely check out Deskbound.
Optimizing your position within your situation is key.
A few Episodes which address sitting.
Episode 15: You Must Defeat The Evil Chair Part 1
Episode 15: You Must Defeat The Evil Chair Part 2
Episode 73: Fight the Airplane Fuzz
Episode 91: Mobilize In the Position of Death by Chair
Episode 276: MobilityWod Google Talk: Desk Bound
Yes, there are hamstring specific episodes