You can easily distinguish CCM from DCM by checking if the inductor current ever reaches 0. If it reaches 0 during the switching cycle, it is discontinuous (DCM). In your case, IL1 is continuous, so I'd say its CCM.
The positive slop of the current wave should be equal to Vin/L, and the negative slope should be equal to -Vout/L. Your slopes are fairly close to that.
On a practical note, notice that your inductor ripple current is extremely low at less than 2%. This might sound like a good thing, but in reality it means your inductor will have to be physically very large to not saturate at 15A and 240uH. Most designs will shoot for 10 to 30% ripple current as a trade off. That is, drop the inductance, increase core gap (if there is one), and so on.