Put all Vinaigrette ingredients in the bowl of a mini food processor or blender. Whir until the ingredients are fully combined and the shallot and herbs become small bits. (Alternatively, you may combine the ingredients in a small bowl or mason jar, but be sure to finely chop the shallots and herbs in advance.)
Put the arugula leaves and roughly three-quarters of the broken crackers, cheese, and cucumber slices in a large bowl (reserve remaining). Drizzle the vinaigrette over top and gently toss.
Transfer the mixed salad to a low, flat serving bowl or platter and top with the reserved crackers, cheese, and cucumber slices. Serve immediately.
TIP A: These crackers can often be found in the gourmet aisle and they're a tempting splurge for holiday entertaining. They often include dried fruit and nuts (in addition to seeds) and have a slightly sweet flavor and crunchy texture. Use any brand or variety that you like.