Blend all pesto ingredients in a food processor or blender until a coarse paste.
Trim green beans and cut into 1 or 1 ½ inch pieces. Blanche in boiling water for 30 seconds and immediately plunge into ice water.
Blister corn on a grill, under the broiler, or over an open flame (great idea I picked up from Smitten Kitchen.
Slice tomatoes into halves or quarters depending on size.
Combine all ingredients and toss with pesto. Keeps well for a day or two in the fridge.