Tonkmin's Kamiwaza ability is to build objects to help others. As a Bugmin, he can demolish pre-built objects and build walls to block anyone.
In the series
Tonkmin first appeared as a Bugmin in episode 1 when he demolised a shade that a salesman was standing under. Yuto summons Turbomin in order to help him chase Bug-Tonkmin. Bug-Tonkmin then builds up a giant wall to block Yuto but Dorirumin drills a hole through it, letting Yuto get through. Yuto then captures and debugs Bug-Tonkmin.
Tonkmin was first summoned by Yuto in episode 3 when he builds him a shield in order to help him deal with Bug-Jaguchimin.
In episode 10, Tonkmin builds a giant ramp for Yuto and Turbomin to go up and chase down Bug-Jetmin.
In episode 14, Tonkmin was summoned by Yuto in order to build a shield and then a giant wall to stop Bug-Senpuumin.