First, get your grill going so you can grill the onions and the pork. You'll want a direct heat and indirect heat space.
Then, mix the herbs, salt, and pepper into the mustard and spread it evenly over the pork loin.
Place the pork tenderloin on the grill over the indirect heat and cook through until the pork is at 130 degrees. Once it's at 130 degrees, move the pork tenderloin to the direct heat and sear each side until it reaches 145 degrees, which will allow the pork to be about medium. Once cooked through, let rest for 10 minutes.
While the pork is cooking, make the pesto. Put the basil, spinach, walnuts, and lemon juice into a small food processor and begin to pulse, adding enough olive oil until the texture is to your desired consistency. Add salt and pepper to taste at the end, set aside.
Also make the dijonnaise by simply mixing all the ingredients together, taste and adjust any seasoning as needed. Set aside.
Next, cut the spring onions in half so that there is a flat side on each. Lightly brush with olive oil, and place on the direct heat of the grill, grilling until just lightly charred. Set aside.
Steam the green beans by placing a half inch of water in a sauce pan with a steam basket and heat until a boil starts. Then place the beans in the basket, place a lid on the pan, turn down to medium and steam for about 5 minutes. Remove and set aside.
Finally, get a large platter out. Slice pork and lay on platter, add grilled onions, green beans, olives, gigante beans, and dollops of pesto and dijonnaise. Add a fresh baguette and serve!