I wouldn't worry about interfering with learning to use a fork or spoon; young children can learn and master all kinds of different things all at once without getting confused. Kids can easily learn to speak multiple languages. Besides, you don't teach kids to use a fork before moving on to the spoon, right? What's important is to expose kids to things at an early age and give them opportunities for regular practice.
Using chopsticks properly requires a certain grip and technique; it's not just a matter of squeezing two sticks together to pick something up. When using chopsticks, the proper technique is to hold the bottom stick stationary while the top stick is the one that actually moves to pick things up.
The training chopsticks like the ones from Edison (pictured above) have finger rings to teach proper finger placement and grip (similar to kids pencil grips) and should help to develop this technique and reduce the initial frustration. They also have fun characters to make it interesting for the kids. It's still not exactly like real chopsticks, but it will help build confidence to make the transition to the real thing. They even have a stage 2 version that has the pivot point at the fingers instead of at the end.
Also it helps if the adults are all using chopsticks, since kids will naturally want to do whatever the "grown-ups" are doing and it will seem normal to them. Finally, you want to serve food that is easy to pick up with chopsticks; there should be small pieces with flat sides and not too oily or slippery. You don't want anything too small or round like peas. Noodles are easy too. Rice is good if it is properly sticky. (This is part of the reason why Asian food doesn't have big slabs of meat like steak or pork chops.)