Fill a small stockpot with water, and add 2 teaspoons salt and 2 tablespoons olive oil. Cut the lemon in half, squeeze juice into water, and add squeezed halves. Remove tough outer leaves of artichokes, and pare down stems using a vegetable peeler. Add artichokes to acidulated water, cover, and bring to a boil. Reduce to a simmer, and cook until leaves are easily removed and heart is tender when pierced with a knife, 15 to 20 minutes. Drain in a colander, and set aside.
Place 1 teaspoon olive oil in a small saute pan over medium-low heat, and add the chopped shallot. Saute until translucent, about 2 minutes. Remove from heat, and add mustard, remaining 1/4 teaspoon salt, pepper, and red-wine vinegar. Slowly whisk in remaining 3 tablespoons olive oil. Serve reserved artichokes with the warm vinaigrette on the side for dipping.