Combine 1 3/4 cups water, 1 1/2 cups corn kernels, and a pinch of salt in a small saucepan.

Bring to a boil, then reduce heat and simmer until the corn is very soft (about 20 minutes).

Transfer the corn and cooking liquid to a blender and puree until smooth, adding water if needed.

Strain the puree through a coarse-mesh sieve into a bowl.

Stir in wasabi paste and salt to taste to make wasabi cream sauce.

In a separate saucepan, cover the remaining 1/2 cup corn kernels with water and cook over medium heat for 10 minutes until tender.

Rub salt into both sides of the tuna steaks.

Coat a large nonstick skillet with cooking spray and heat over medium-high heat.

Sear the tuna steaks for about 3 minutes per side.

Remove the tuna from the skillet and place on a platter.

Reheat the wasabi cream sauce, adding salt to taste if needed.

Drain the cooked corn kernels.

Pour the wasabi cream sauce over the seared tuna steaks and scatter the cooked corn on top.

Serve immediately.