If you left the motorcycle somewhere else, it is possible to climb the sand pile on foot. However, you will eventually need to jump the motorcycle onto the pile, as shown in this section, in order to continue.
To get on top of the pile, stand facing north, with the sand pile directly in front of Lara, and examine the various tiles used to make up its surface. Note the triangular tile on the left side of the pile just above the brown floor.
Walk to the upper point of this triangle, and pivot/sidestep Lara into the corner, so her right foot is as far to the right as possible, and she's standing as far up the slope as possible.
Pivot on the spot to face the left side of the top of the sand pile and the corner of the striped wall behind it. Notice the black, vertical line in the striped wall. That's approximately where you're aiming.
Jump forward without holding Action...
...and Lara should land just at the edge of the flat spot on top of the pile.
Now you can climb the ladder to get to the STREET BAZAAR. Or, if you've already explored that level and opened the small door (just beyond Lara's head in this screenshot), you can drive through that door on the motorcycle.