Elitefts.com™ Education Director Mark Watts performs a set of One Arm Dumbbell Snatch.  This is an excellent Olympic Lift variation that improves lower body power and shoulder stability.

Execution:
1.) Stand in the Athletic position with the dumbbell centered and your shoulder blades "in your back pocket"
2.) Push your hips back until the dumbbell is between your knees and you feel a stretch on the hamstrings.  Keep the arm relaxed
3.) Drive your heels and jump
4.) As the dumbbell is ascending, descend into the power position by "punching" the dumbbell overhead.
Benefits of performing this exercise with one arm include additional stability, safety, and logistics in a team setting.  Additionally, there is a carry-over in technique with the barbell snatch

Stability:  Stabilizing the dumbbell overhead in the catch position adds an additional plane of movement when performing with one arm

Safety:  If an athlete catches the dumbbell in an awkward position (namely too far back), they can simply turn their shoulders toward the dumbbell to achieve a better biomechanical position.  Also, the athlete has the other hand to assist in lowering and resetting.  Using a barbell may require teaching the athletes to "bail" on the snatch, where that in not necessary with the DB snatch

Large Groups:  Using one dumbbell may not reduce the total time it takes to train, but it will allow for a more productive work to rest ratio.  For example, if 4 athletes are using a pair of dumbbell, 2 of the athletes are training at all times.

Technique:  Along with a one arm barbell snatch, performing this lift with one arm can help teach the athlete to use their hips more if the athlete is not accomplishing triple extension.  The athletes will not be able to muscle the weight up and will need to "get tall" quickly in order to generate force.  The one arm dumbbell snatch can also serve as a lower body deload because the total amount of weight used is less than a barbell.

Coaching Cues
"Shoulder blaseds in your back pocket"
"Push the hips back"
"Jump and Punch"

Common Technique Discrepancies:
The DB is swinging way in front = try standing directly in front of the athlete
The Arm is bending too early = have the athlete turn their elbows out
Not in an athletic position during the catch = harp on resetting the feet and have the athlete squat into an athletic position after the catch or pause the catch position.