On this page of the trophy/achievement guide to Star Wars Jedi: Fallen Order, you will find detailed information on how to unlock Kickoff trophy/achievement. You get the trophy/achievement for defeating an opponent with kicks only.
This trophy/achievement requires some preparation. You need to purchase Evasive Kick skill, which becomes available after unlocking Force Push in chapter 2.
Find a lone Stormtrooper. It can be a Stormtrooper equipped with a melee weapon or a blaster -if you chose the latter, you will have to stand very close to that enemy to "force" him to stop firing and try to hit Cal the stock.
Run around the Stormtrooper to provoke him to attack - it must be a normal attack, not a red one! Press the dodge button (Circle / B on the controller - example in picture 1) at the right moment and follow it with an attack (Square / X on the controller). Cal must kick the Stormtrooper instead of using the lightsaber (example in picture 2).
If you are playing on the normal difficulty level, you will probably have to kick the enemy three times. You can't use any other attacks - don't use the lightsaber and Force.