Disclaimer

Hop parallel to the obstacle, on the side of your front foot.

1° After a compression hop, crouch and lean towards the obstacle to pre-load the tire. Keep your ankles flexed.

2° Bounce back from the compression, springing up your ankles and swinging your free hand up to boost the extension.

3° Instead of landing directly with your tire, clamp your front foot pedal onto the edge and lean your shoulders well over it.

4° From there, pull on the seat up in one smooth extension on your front foot, while moving up the other pedal.

5° Spinning the wheel, finish off the move leaning further over the obstacle and pulling the uni over in one hop.

6° Flap your free hand down again as you hop the tire over the pedal-grab spot. In air, push the back pedal to horizontal.

You should land with both pedals level to the horizontal, like at the start.
See the move in a video.

Swing up on a slanted wall

Holding to a pedal grab
When you land a pedal-grab, you must lean your shoulders well over the front pedal and avoid any pressure in the back pedal as it would put you off-balance. From that position, swing again your free hand up for the finishing hop. Because you are already leaning over the obstacle, the second hop will naturally re-adjust the unicycle beneath you and bring the tire onto the obstacle. If you don't have time to re-adjust your pedals during the hop, make a few correction hops and you're done!

Tuning the move on a rail

Maximise your impulsion up by bending forward at the waist and spring back up, flexing up both the knees and ankles. For the second hop to land on your tire, center your back foot on the other pedal and while holding the seat firmly, hop from the toes of your front foot to get maximum leverage from your ankle movement (more spring than if you were resting on your heel).

A little bit of training
Initially, just focus on the second part of the pedal-grab. Hang the uni directly by the pedal you would grab on your front foot and stand on the edge of the obstacle, putting all your weight on that pedal. You are virtually balancing on one foot, let the unicycle drop with the back pedal at the bottom and put your back foot on the bottom pedal but with no pressure on it, else you'll fall off-balance. Then pull on the seat until the uni swings up with your back pedal is level or a bit higher than the hooked front-pedal. In the same rotation, pull up the seat further and jump off when your back pedal is nearly vertical (you only take the impulsion on your static pedal). In air, push the top pedal back to horizontal, level again with the front pedal, so that you land with both feet aligned.

Crank grab onto some wall

Crank grab or crank-stall
A variation of the pedal-grab is to sidehop and hook not only the front pedal, but also the corresponding crank arm. This locks the unicycle onto the edge of the obstacle while you lean over the landing spot on one leg. Again, you need a second hop to finish on your wheel. Here you don't swing the unicycle, but hop without tire-compression. To optimise your second impulsion, tilt the uni further towards the obstacle and use both legs for your extension. If the crank arm is well locked over the obstacle (you can step on it a bit), then you can put quite some pressure on the back pedal, as long as you tilt the unicycle. Here you need to use your arm swing even more, as this is the only momentum you can get.