I got this recipe from the Catch of the Day, Honolulu's Finest Seafood Recipes. This is by chef Roy Yamaguchi, owner and chef of several Roy's Restaurants. It is really good, and although it takes a little bit of prep time, it's well worth it.
Combine chopped shrimp with garlic, chili paste, and mushroom soy. Reserve for 30 minutes.
Chop all peppers and onions into small squares and mix together.
Have ready a HOT grill and hot saute pan. While grilling the ahi steaks till your desired doneness, keep rice and Chinese peas warm. In hot saute pan, quickly add vegetable and sesame oils and bring to smoking point. Quickly add bell pepper/onions mixture and saute for 30 seconds. Add marinated shrimp and saute for 15 additional seconds, stirring constantly. Remove from heat.
Place Chinese peas in center of each plate. Place ahi on top of peas. Spoon bell pepper and shrimp mixture over each ahi steak.