Tuna Boats on Spinach GF

Why I Love This Recipe
note: updated to gluten-free November 16, 2010 (no modifications required)
Ingredients You'll Need
1 green bell pepper (or red, or yellow)
1 3 oz pkg chunk light tuna*
1 small avocado
1 small jar capers & liquid
walnut oil
balsamic vinegar
chopped or halved walnuts (2-4 small handfuls)
bunch spinach (for 2 to 4 servings)
salt & pepper
Directions
boats:
slice peppers into quarters making 4 "boat" shapes (remove veins, seeds, stems, etc.) set aside.
cube avocado. fold cubes into bowl with the drained tuna, 2-4 tbs of the capers (plus a little caper liquid), and salt and pepper . don't mash.
scoop 1/4 of the avocado/tuna mixture into green pepper boat. repeat for all boats.
dressing:
pour about 2 tbs of the balsamic vinegar into small bowl, whisk in stream of walnut oil (about 2 parts vinegar to 1 part oil works well--just test it as you go.)
toss dressing with the spinach, place dressed bunches of spinach leaves in bowls, sprinkle with ground pepper and with walnuts. top each bowl with 1 or 2 tuna boats.
Adjust quantities to taste (double the tuna if you want more protein.)