The MAX16826 supports a maximum 4A, or 1A per channel. If you need 2A for instance, or 500mA per channel, the device can satisfy that need.
Using the first channel as an example, R31 = VCS/500mA, where VCS is between 97mV and 316mV, configurable over I2C. Since the maximum single channel current is no larger than 1A, the maximum resistance should be no smaller than VCS/1A.
The power dissipated in the resistor is the square of the current multiplied by the resistance. With this, one can choose a resistor with the appropriate power rating based on the design rules and thermal testing. For example, if your peak inductor current is 6.5A, you can select the part based on R12 = 200mV / (1.2 * 6.5A). The 200mV is the trip voltage above which the controller shuts down operation to protect the circuit. A fudge factor 1.2 is added to effectively tolerate a higher peak.