Using a serrated knife, cut ½ inch off the top of each artichoke. Cut each in half vertically. With a scissors, trim the pointy ends off the leaves. Using a spoon, scrape out the fuzzy choke in the center and discard.

Rub artichokes all over with lemon.

Fill a large pot with water and fit with a steaming rack. Place artichokes on rack and steam until they are tender and easily pierced with a fork, about 30 minutes.

Set aside to cool for 15 minutes.

Meanwhile, preheat grill to high heat.

In a small bowl, combine mayonnaise, sweet Asian chile sauce and sriracha; blend well. Set aside.

Grill artichokes, cut side down, on a greased grill rack, until nicely charred, 4 to 5 minutes.

Serve hot with dipping sauce.