tgharold answered pretty well how much delta-v you need in the ideal case. To get from orbit to ground you need at least as much delta-v as the orbital speed at ground level. But he didn't say anything about how much thrust you need.
You can look up the surface gravity acceleration of a body in the tracking station or on the wiki. For Minmus, it is 0.05g or 0.491 m/s². When you have a craft which can accelerate at least that fast, it is capable to hold its speed constant while descending. But to land, you need to reduce the speed to zero before surface contact, so you need more acceleration. How much more acceleration? That depends on how efficient you want to land. The later you start your deceleration burn, the less delta-v you need. That means the more thrust you have, the closer to the surface you can dare to start your break maneuver, which means you will be closer to the ideal delta-v budget.
So how do you calculate the acceleration of a vessel? Simply divide the thrust by the mass. A 10 ton vehicle with a LV-909 "Terrier" (60kN) engine has an acceleration of
60,000 / 10,000 = 6 m/s². Subtract the gravity of Minmus and you have a remaining deceleration of about 5.5 m/s². That means the vessel can stop a 200 m/s descent with a 36 second burn.